


Bycatch

by LibbyLune



Category: One Piece
Genre: Adult Themes, Alternate Universe - Fantasy, Alternate Universe - Merpeople, Angst, Eventual Happy Ending, Graphic Description of Injury, M/M, Slow Burn, atypical reproductive biology, but it’ll be worth it, lots of really specific fish stuff
Language: English
Status: In-Progress
Published: 2020-05-31
Updated: 2021-02-04
Packaged: 2021-03-03 03:20:14
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 7
Words: 47,571
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24407923
Author URL: https://archiveofourown.org/users/LibbyLune/pseuds/LibbyLune
Summary: bycatch (noun / ˈbaɪ.kætʃ): fish or other sea creatures that are caught unintentionally by people who are trying to catch other types of fish,ex., injured merpeople caught while in pursuit of other exotic sea monsters.  Gotta make up those lost profits somehow.
Relationships: Roronoa Zoro/Vinsmoke Sanji
Comments: 83
Kudos: 337





	1. Blood in the Water

**Author's Note:**

> most of the beginning (uh... first two chapters) of this is basically medical horror disguised as a mermaid AU, so if you are sensitive to descriptions of injury and rough first aid mixed in with your angst and banter, this is your warning.
> 
> You can see my specific mer-Sanji design here on [my Twitter](https://twitter.com/libbylune/status/1266045057968242689?s=21).

Niji flashes around the school of fish, tightening the edges of the swirling ball. Yonji laughs, out of sight beyond the whirl of sparkling scales. Sanji can’t see Ichiji either, but he knows his oldest brother will be lurking beneath the school, forcing the fish up into Niji’s reach.

Sanji floats just out of range, carrying the nets his brothers will use to bring their catch home. He knows better than to try and help - it’s far too easy for _accidents_ to happen, and this isn’t a safe stretch of sea. Waiting until the violence is over is wiser, even if his brothers will mock him for it all the way back. Just because he isn’t a shark, because his marine half looks more like a sailfish and he got his mother’s seahorse flexibility instead of their father’s unnatural modifications.

Out this far, all the predators are at the top of the food chain, and there’s only so much prey to go around. Sharks - ordinary ones, not just Sanji’s brothers - will notice the commotion easily, and once Niji gets into the school with his viciously elongated tail, the blood in the water will only draw competition in quicker.

Watching the panicked fish out of the corner of his eye, Sanji looks out into the deep ocean around them. His brothers don’t have the right kind of countershading to disguise them out here, but plenty of other sharks would be difficult to spot until they get close. It’s a bright day above the waves, casting distracting shafts of light through the water and making the reflections off of the fishes’ silver scales that much more intense.

Sure enough, Sanji sees a few large sharks cruising in slow arcs, ghostlike shapes of blue and white silhouetted against the endless depths. They’re distant enough that they aren’t a threat. Not many sharks will engage with merpeople until there’s blood in the water, and fewer would challenge a Great White like Ichiji. Sanji is less worried about those sharks than whatever his brothers might do.

“Now!” Ichiji commands, and Niji darts through the tight ball of fish, thrashing around with his tail. Blood begins to spread through the water, some fish sliced apart by Niji’s attack, many more drifting stunned in the chaos. Howling with laughter, Yonji loops around the edges, catching fleeing fish with his bare hands and even his teeth, while Ichiji only deigns to finish the ones that come too close.

In seconds the scene is still, the remnants of the school scattered into the blue. Ichiji waves Sanji forward, as Niji idly chases a handful of fish too confused to escape properly.

He sees Yonji’s cruel grin, but it’s not enough warning. One last panicked fish darts across Sanji’s vision, and Niji swoops after it, battering Sanji in his sharp turn. The tip of his tail whips across Sanji’s side, opening a gash down his tail not far from his hips.

Sanji yelps and tumbles through the water from the force of the impact, trying to lift his dorsal fin to stabilize himself. It won’t open correctly, an unfamiliar and painful drag preventing him from raising the spines to open his sail.

“Get out of the way, idiot,” Niji hisses, somewhere above - below? - not far from him. 

“Nets,” Ichiji demands, even closer.

“We’ve got company,” Yonji comments.

Sanji stops spinning, the effort of moving his tail agitating the gash there. It’s deeper than he thought at first, blood flowing freely to cloud the water around him. The water feels wrong as the current flows along his back, more disturbed than it should be. Twisting to get a look at himself, Sanji gasps, both at the pain in his side and at the state of his fin. The membrane is split roughly in line with the gash, and several of the strong spines supporting it are snapped and bent.

Ichiji grabs the nets from his hands, and Sanji has the mildly hysterical thought that his brother’s reddish coloration is much better suited for disguise in waters like this, dyed with blood. It matches Ichiji too well.

“Might want to hurry,” Yonji prods, gesturing past the mess of stunned fish and chum they’ve created. 

Several ordinary sharks are gliding closer, too entranced by the taste of blood in the water to think twice about approaching. Niji snickers and fakes a lunge, scattering a couple of the smaller ones, but a few larger individuals merely continue their slow inward spiral.

Clutching at his tail, Sanji’s eyes dart between the hungry predators and his brothers, as they scoop their catch into the nets. It does nothing to lessen the blood, of course, and now it’s easier to tell what the sharks are circling in on.

Most are more interested in the nets, the easier meal, though all the sharks are still giving the mermen a wide berth. That isn’t what has Sanji’s blood running cold, even as a thin trail continues to leak from his wound.

One of the sharks is a massive mako, quite possibly the largest Sanji has ever seen, and it's gliding in toward Sanji, where he’s separated somewhat from his brothers. From the amused expressions on their faces, those three have noticed the same thing.

Sanji is the fastest thing in the ocean, but a mako shark isn’t far behind on a good day. This is not a good day.

“Uh oh,” Yonji grins, tying off his net and snapping at a smaller shark that ventured too close. 

He won’t get any help from there. Panting, the water feeling colder as his heart begins to race, Sanji tries to guess how bad his tail really is.

“Better get going, or we’ll be late for dinner,” Niji says, hefting another net. “I want to eat some of these while they’re still fresh.”

Sanji can’t manage a full stroke of his tail without stretching the gash. More blood pulses out when he does, and the pain leaves black spots in his vision. His balance is off due to the damage to his sailfin. 

The mako swoops closer. Several of the other sharks back off.

“Thanks for the help, failure,” Ichiji idly says. A powerful sweep of his tail shoots him forward, Niji and Yonji following in his wake. Their speed buffets Sanji, and the boldest ordinary sharks dart in to snap up the bits of fish they left behind.

He’s going to have to make a run for it, and hope that he can find somewhere to lose the mako before his tail gives out. Feinting after his brothers, Sanji dives in the other direction and tries to ignore how every stroke of his tail feels like it’s pulling the wound further open.

There’s a jellyfish bloom not far from here, giant ones clogging nearly a mile of ocean in an area of mild currents. If he can get there, the shark won’t follow him into the bloom. Sanji will have to be careful of their stings, but navigating the jellyfish will be easier than outswimming a mako shark in this state.

Closing the distance between them in seconds, the shark lunges and Sanji barely twists to avoid it. He gets a good look at its teeth as it flashes by, row after row of ivory daggers in a jaw nearly wide enough to swallow Sanji’s entire head.

He’s barely getting enough oxygen, gills pressured by his speed. Keeping his eyes on the shark as it circles back around, Sanji gets a terrifying glimpse of its cold black gaze just as the fringes of the jellyfish bloom come into view.

Soft pastel colors drifting in the water, like candy, like the sunset in the clouds over a beach of white sand while the shitty old man yells about spices. Tentacles trailing after, and Sanji will have to avoid as many as he can, but a few stings won’t debilitate him, it would take a lot of their venom to kill something his size. He can rest on one of the bells for a while, get a better look at his tail -

The shark is coming back, racing up from an angle too close to Sanji’s own momentum to avoid. He tries to roll, staggered by the unfamiliar drag of his damaged fin, and the shark’s teeth slice into his tail, right where Niji ripped him open earlier.

Sanji screams, whacking at the shark’s sensitive nose, and when it lets go, bludgeons it as hard as he can with his injured tail. Normally he can put a lot more force into a blow like that, but it’s enough to push him away from the creature.

For a critical few seconds, the shark is stunned. Sanji races for the bloom, tail going numb from the pain as ribbons of blood follow him through the water. He’s going too fast to adjust his trajectory, crashing through a few clusters of trailing tentacles until he comes to a stop against a massive jellyfish’s bell.

Twitching under the stings, Sanji scrambles back, clawing his way deeper into the bloom while the shark recovers, circling in agitation in the open ocean beyond. Before long it leaves, gliding away until its sleek shape melts into the backdrop of endless blue.

Whimpering, Sanji tears away the tentacles he’s tangled himself in. They leave welts on his pale skin, and the sting is barely less where they cling to the scales of his tail. One catches in his ragged wound, but Sanji can’t feel anything there anymore.

Still, pulling the tentacle free releases another cloud of blood, and Sanji can tell that the trembling in his body isn’t only fear. He doesn’t have any supplies with him - Ichiji dragged him out for their little hunt with no warning. If the bleeding doesn’t slow soon, Sanji will be too weak to fight off the jellyfish venom, and he has no way to stop it.

Sanji collapses against the jellyfish he’s landed on, and tries to get his breathing under control. Its surface is cool and soft beneath him; soothing. The light diffused through the surrounding bloom catches a glow of color through the jellyfish closer to the surface, refracting in odd shadows.

He should try to get to the surface. The wound will stop bleeding faster if he can get it dry. With that plan in his head, Sanji pushes himself up on trembling arms.

Pulling himself through the bloom, Sanji tries to decide which island is closest. This area is rife with little sandy atolls, once he can get out of the deep ocean. Most of them are uninhabited, so he should be safe once he reaches one.

A smaller jellyfish wobbles under his weight, and Sanji slides off, falling through a cluster of tentacles before bouncing off a more stable bell. The fresh stings make his strained muscles seize and he slips again, clinging to the jellyfish beneath him until the shuddering stops. He’s getting close to the edge of the bloom, the pastel colors darkening against the backdrop of the open ocean.

After a few more precarious minutes, Sanji can see out into the clear water. There’s no sign of the mako or any other predators, so he pushes himself off of the last jellyfish and gingerly tries a few strokes of his tail. If he goes slowly, he should be able to swim without aggravating it too badly. He doesn’t have a choice, anyway, he can’t stay here, and the lethargy is only getting worse -

He crashes into something. Sanji flails, trying to get away, but it’s _sticky_ and he can’t see anything, it’s just trapping his hands and clinging to the side of his face and when he thrashes his tail gets stuck in it too. Panicked, Sanji can’t maintain the presence of mind to be careful, and his struggling agitates his wound again, a fresh burst of red coloring the water.

Before he can worry about more sharks finding him, the thing jerks Sanji upward. He coughs on the rush of water washing slantwise through his gills, and sees the surface approaching at a shocking rate.

“What is it, what is it, that’s not an island turtle -”

“Stand _back_ , idiot, you’ll fall overboard-”

“- it’s a fish? It’s so big, do you think Nami will let us eat this one -”

“- careful! Oi, Luffy, you’re too close -”

“- it’s a person? A person and a fish? Zoro, what -”

Yanked into the glittering sunlight, Sanji can’t make any sense of his surroundings. He gets a momentary sensation of weightlessness, so much more unsettling than the swooping joy of a good jump, and then slams into a hard surface. Cracking his head against whatever it is hurts almost as much as banging his tail into an angled edge of what swims into his pain-spotted vision as a small boat, and Sanji screams again.

The dry air scrapes his throat, his lungs not ready for the change. Someone else screams too, and voices are yelling, and something that isn’t Sanji bangs against the boat. Sanji himself thrashes around, only getting more tangled in whatever pulled him up, and splashing blood everywhere.

“It’s a monster!” a voice screams. “Oh my god, blood, I’m definitely coming down with allergic-to-monster-blood-itis, oh my god -”

“Monster! Is it? What kind of monster are you, hey, hey -”

“Sit _down_ ,” a third voice growls. “It’s a mermaid, duh, now stop -”

“Mermaid! Zoro, it’s bleeding, what should we do -”

“Oh, it’s a mermaid? I mean, I definitely knew that, the Great Captain Usopp knows all the creatures of the sea -”

“But it looks like a fish, can you eat mermaids?”

Sanji struggles harder at that, and manages to right himself enough to raise his head - small boat, two shocked faces, _humans_ \- before something slams into his back, forcing his face against the bottom of the boat.

“Stop!” the growling voice demands, right next to his ear, and stunned as he is, it takes Sanji a few seconds to realize that the owner of the third voice is sitting on top of him, pinning his tail and immobilizing his head with one hand.

The other is holding a knife, practically the only thing left in Sanji’s field of vision. He goes still, heart hammering as he gasps for air.

“So much for island turtles,” the voice mutters. “Your invention is shit, Usopp.”

“Hey! It totally worked, you just caught the wrong thing!”

“Shishishi! Nami’s gonna be so mad! What happened to you, fish guy?”

The hand holding him down yanks him up by the hair instead, and Sanji gets his first real look at the humans in the boat. A weirdly cheerful boy in a straw hat, crouched on his heels up on one of the small boat’s bench seats, grinning despite Sanji’s blood splattered all over him. Sanji can’t see much of the second guy beyond curly hair as he cowers at the far end of the boat, but he’s much more concerned about the third person still sitting on his tail.

When Sanji doesn’t respond, the kid with the hat cocks his head to one side, smile sliding off into a wide-eyed frown. His gaze shifts over Sanji’s shoulder. “Hey Zoro, can mermaids talk?”

“It can sure scream,” the coward mutters, peering over the seat.

Sanji yelps as the third guy hauls him farther back, bending his spine too far and releasing his hair to twist his arms behind his back and drag him sideways, so the man can sit over him and poke at his wound, knife abandoned to the side.

“Shark attack,” the guy comments, digging his fingers into the ragged mess. Sanji thrashes and whimpers, but the man is too strong and Sanji is too injured to resist him. “Mako, looks like.”

The guy leans over him to toss something to the coward, and Sanji gets a glimpse of green hair. Algae green.

“Oh shit, must’ve been huge,” the coward says, holding up a tooth. “Look at this thing. Why, one time, I fought off a shark that must have been three times -”

“How big was it?” the cheerful kid demands, eyes back on Sanji. “Can you talk? Show me with your hands if you can’t talk - Zoro, let it go, I wanna hear about the shark -”

“No way,” the algae-head grumbles. “I’m not letting a monster loose in this boat. Besides, look at this mess, it’ll probably die any minute.”

Panting in the bottom of the boat, Sanji can’t quite disagree. Everything hurts at this point and he can’t make sense of what’s happening, what these people want, if they’re just going to throw him back overboard or kill him themselves. But he doesn’t want to die like _this_ , with strangers talking over him like a dumb beast and a brutish human’s fingers in his side.

“It’s not that bad,” he coughs, spitting up seawater. And blood. The liquid is pink as it drips off his chin into the bottom of the boat.

“I think it really is,” the coward immediately retorts.

“You can talk!” the kid exclaims. “I’m Luffy! This is Usopp, and Zoro! Do mermaids taste good? Usopp, where are the bandages, we have some right?”

Usopp starts rummaging around under the seats, and Zoro sighs. Twisting to get a look at him, Sanji meets with one cold eye and a steely glare.

“Waste of supplies,” the guy mutters, poking at the edges of Sanji’s wound again, “but maybe the witch can find a buyer for a mermaid instead.”

Sanji hisses weakly, unable to stop his tail from spasming, and Zoro shoves him down again. Luffy hops over with an armful of bandages, and picks at Sanji’s torn-up sailfin.

“This is all busted,” he comments. “Hey, fish guy, was that the shark too?”

“Thresher shark,” Sanji gasps. Close enough, and remembering Niji’s smug face puts a spark of rage in him that’s almost calming. It burns away a little of the pain.

“Wow, two sharks? That’s a bad day,” the kid says, dropping his fin and poking at his tail instead, where the algae-head is still examining the ragged edges of the bite.

“If you wanna bandage it up, this should just come off,” Zoro says, and lifts a more-than-fist-sized piece of Sanji’s tail _straight out_. Well, it’s connected by a few threads of muscle and skin, but no wonder it hurts so bad! Sanji gags, panicking anew, and tries to get away.

He doesn’t get anywhere, the algae-head grabbing him by the back of his neck and snarling at him. The man picks up his knife, and Sanji gives up.

“It looks like fish inside!” Luffy chirps. “That piece looks like fish, hey, Zoro, can I eat it?”

Sanji gags again, trembling as the man shifts above him. He feels a dizzying tug over the background pain of the wound, and a sharp pinch.

“Gimmie!” the kid demands, and Sanji’s trembling turns into wracking shudders.

“You can’t eat this!” Zoro says, leaning back with a knee braced against Sanji’s hip. “What have I told you about eating raw fish?!” Sanji hears the straw-hat kid whining, gets a glimpse of something red in Zoro’s hand, and passes out.


	2. First Aid

“Uh, Zoro, I know you said the problem was getting a parasite from eating raw fish, but should you really let him eat that? Even cooked, I mean, sailfish doesn’t even taste that good and it’s not _normal_ sailfish, come on -”

“Stop him yourself if you care so much,” an almost-familiar voice grumbles.

Sanji blinks, taking in the feeling of sun on his dry skin and sand under him, the sounds of several people moving around, and the scent of… cooking… fish… 

He wants to scream, but dryness catches in his throat and he chokes, coughing and gagging instead. As he tries to roll over, Sanji discovers that his hands are tied behind his back, just above the first spines of his dorsal fin. And his tail still hurts like nothing he’s ever experienced.

“Oh, hey, uh, are you okay?” the first voice says, and a face hoves into view. It’s the cowardly one; Usopp, Sanji remembers. His nose is ridiculous, even by ocean reef standards, and Sanji has seen some really goofy-looking parrotfish.

“Is your friend _eating_ my _tail_?” Sanji demands. It doesn’t come out as fierce as he wants, his voice too tired and hoarse. Not to mention horrified.

“Uh,” Usopp squeaks, glancing farther up the beach. “Only a little?”

Sanji feels sick. The smell is no different from any other fish he’s watched the old geezer roast. As he stares at the long-nosed stranger, the guy’s gaze won’t settle, darting from Sanji’s eyes to his tail, over his shoulder and along the beach and back.

“Ooh! It’s awake?” The kid with the hat bounds over, gripping a chunk of something on a skewer that Sanji can’t bear to look at more closely. “Hi!”

“Hi,” Sanji repeats. The kid takes a bite off the skewer.

Sanji throws up. Usopp looks green, and the mess Sanji has just made is red, a significant percentage blood as it soaks into the sand. Must’ve been worse off than he realized.

“Gross,” Luffy says, and takes another bite.

What did he do to deserve this? His family likes to tell him he's a failure and a waste of space, but surely he doesn’t deserve to dry up under the sun while watching a lunatic human _eat_ pieces of him.

“I’m gonna get back to work,” Usopp mutters, scampering out of Sanji’s sight.

There’s not much to see, from this angle. Beach, a featureless stretch of ocean not far away but entirely out of Sanji’s reach. Now this freak settled on his haunches in the sand in front of Sanji, watching him with a curious smile and the strangest lack of empathy Sanji has ever seen on an expression so otherwise harmless.

“You’re a sailfish?” the guy asks.

“Not exactly,” Sanji says, shock flattening his voice.

“It’s a mermaid, Luffy,” the algae-head shouts in tones of clear exasperation.

“Mer _man_ ,” Sanji mutters, as if it will matter to any of them.

Finishing his skewer, Luffy rocks back and forth on his heels. “Yum. What’s the ocean like? I can’t swim.”

“But you’re a fisherman,” Sanji protests, instead of whimpering in panic.

“I’m not a fisherman!” the kid says indignantly. “We’re pirates!”

“We’re not pirates yet,” Usopp calls from down the beach.

“We’re not even fishermen, at this rate,” Zoro grumbles.

Maybe this will make more sense if he can see properly. Sanji tries to sit up, but between his injured tail and bound arms, even his impressive core strength is barely enough. He can’t help making a strained sound, and Luffy just keeps watching him with that curious face.

No, nothing makes more sense. It’s a tiny island, barely more than a white sand beach with a windbreak of exposed reef and some mangroves at one end. The humans’ boat is dragged up nearby, and it looks even smaller now. Nothing else but a half-assed shed with a palm-frond roof and three open sides, and a fire guttering beside it.

The algae-head glares at him, sitting with Usopp under the shade with some kind of sand-encrusted net laid out between them. Beside the guy are three long swords, while Usopp is surrounded by implements Sanji can’t even name. Well, at least if they decide to kill him it will probably be quick.

“We’ll be pirates once we have a ship,” Luffy says, unfazed. “And I want the best ship, so Nami says we need money. So Franky will build it for us.”

“That’s… how commerce usually works, yeah,” Sanji manages. Maybe he’s hallucinating this conversation. After Niji, and the shark, and the jellyfish, it’s not impossible.

“Speaking of money,” Zoro growls, standing up and dusting the sand off his pants. “You and Usopp should go ahead and take the regular fish back to town. I’ll stay and deal with this. See if I can’t still catch one of those turtles.”

“Without the boat?” Usopp asks. The algae-head shrugs.

“Aw, I don’t wanna go back yet,” Luffy complains. “I wanna hear about the ocean. Hey, fish guy, do mermaids have pirates?”

“Focus,” Zoro snaps. “You’re going with Usopp, because he can’t lift all those fish, and he’ll just run away if someone tries to take them. He’s going because he can’t fix that stupid net out here, and without him you’ll get distracted and let someone con you out of the fish before you can get them to Nami. I’m staying, because the witch will be pissed if we go back with just a bunch of ordinary fish and I don’t wanna deal with that.”

“As insulted as I am, I can’t argue,” Usopp mumbles. “I really can’t get this clean without more space. And less sand. Mostly less sand.”

The section of the thing in his hands is almost transparent, and seems to be sticking to his skin. 

“What is that?” Sanji demands.

“The Spectacular Inventor Usopp’s Seaweb!” the guy proudly says, holding it up to Sanji. “Mostly dusk spider silk, but woven into the perfect net for catching wary sea monsters -”

He clams up, looking guilty. Sanji glares, and Zoro picks up one of his swords, laying a not-so-casual hand on it as he tucks it into the sash around his waist.

“Do you have any idea how much rich idiots will pay for a pet island turtle?” Zoro asks. Sanji shakes his head, even though the question was clearly rhetorical. “Neither did I, but Nami sure does, and if there’s anything that witch is good at, it’s making dirty money.”

“It’s very effective,” Sanji snarls. “Just watch out for the bycatch.”

“Maybe you should be glad,” the swordsman challenges. “Got your dying ass some help.”

“Oh yes, I’m so thankful to fall into the hands of amateur exotic pet traders,” Sanji hisses, momentarily forgetting just how precarious his position in those hands is.

“Dunno who would want something like you,” Zoro growls right back, “but I’ll leave that up to the witch.”

“Uh, Zoro, isn’t that… I mean, turtles are one thing, but…” 

“Just go back, ask Nami what she wants done,” Zoro snaps.

“Shishishi! Zoro is so funny. Okay! Usopp and I will go see Nami, but we’ll be back real soon, so don’t wander away!”

“As if I would!”

“You so would,” Usopp mutters, so quietly that Sanji thinks he’s the only one who heard. 

The three of them split into action without any further discussion. While Usopp packs up his tools, Luffy scampers off to the boat, and Zoro strides down the beach, climbing out into the edge of the mangroves to retrieve a livewell. The man carries it easily, even as it shakes from the desperate thrashing of the catch inside.

Sanji finds himself empathizing a little too much with the basket of red snapper, and looks away. 

The pain in his tail has settled into a heavy throb. He’s not bleeding through the slipshod bandage covering the bite, and while he can still feel the effects of the jellyfish venom, it’s not so bad. Despite that positive news, he’s really getting dangerously dry, out here in the direct sun. Now doesn’t seem like the time to bring that up.

Loading complete, the humans raise the boat’s single sail, and Zoro pushes it off of the beach with the other two already inside. Watching the muscles bunch and heave beneath the man’s thin shirt, Sanji only feels more anxious.

“See you tomorrow!” Luffy shouts, grabbing at his hat with one hand as he leans out over the side of the boat. Usopp grabs him by the back of his vest with a yelp.

“Or maybe the next day, you know how Nami is!” the coward adds, once Luffy is safely back in the boat. Then the wind catches the sail, and the two wave at the island for a few seconds before rushing to control the boat.

Zoro doesn’t wave back. The little boat flits away over the waves, the swordsman staring after it, and Sanji stares up at the man’s broad back. He’s strong. Nothing to Sanji if they were in the water, but beached like this, with his hands tied? Even uninjured, Sanji wouldn’t be able to get away from the algae-haired human.

He wonders if his trepidation shows on his face when the swordsman turns around. The human is expressionless, and Sanji has no idea what to expect. If Zoro is going to kill him, he might as well get it over with.

Whoever this Nami is - their boss? - it seems like Zoro doesn’t want to make that decision without her, but not out of any kind of respect. Sanji has no doubt that his death would suit the swordsman fine, if the human could be certain of avoiding any consequences. He seemed eager enough to get rid of Sanji like any other monster when they first pulled him up.

It could still look like an accident. Sanji is fairly sure by now that his wounds aren’t life-threatening, but there are plenty of complications that could change that. The swordsman could just stab him, up through the bite where it won’t show, and tell his friends any number of believable things.

None of this analysis has any value without some idea of what the algae-head is thinking, and the man isn’t giving away anything more than mild distaste. They’re staring at each other now, and Sanji has to wonder what the man even sees.

From the waist up, Sanji knows that he looks essentially like a human. He’s paler than most and his gold hair is unusual, but he understands those differences to be things that many humans find attractive, rather than unnerving. He doesn’t have sharp teeth like his brothers, or spiny ears like Reiju, or even webbed fingers like many other mers. The extra membrane that protects his eyes is invisible until it moves, and his gills lie low against his neck, hardly noticeable when he’s above water.

It’s the rest that matters. His tail. The now-broken fin that starts halfway down his spine. The near-legendary status of his species to these weak-lunged surface dwellers. The fact that this human in particular seems to see him as a threat.

Zoro lays a hand on his swords again, all three now hanging from the ratty sash around his waist.

“I need water,” Sanji says. Nothing to do but push forward as if the human will value his life. He gestures at the dull, dry patches spreading across his scales. Beyond that, he’ll get a sunburn if he’s stuck out here much longer, and he never wants to remember how the old geezer laughed the first time that happened.

Blinking, Zoro takes a step toward him, pausing as if surprised before striding around behind him. At first, Sanji thinks the man is going to untie his arms, and the bubble of hope is light in his chest.

The swordsman only checks the knots, coming back around Sanji’s side with the end of the rope in his hand. “Okay,” the algae-head says, with a curt gesture toward the ocean.

“How do you think -?!” Sanji gapes at him, rage and humiliation coloring his cheeks. There’s no way he can move himself that far. Bending his tail hurts, his skin is dry enough to start cracking, he needs his hands to support his weight if he wants to move across land - even if he could use his tail properly, he’s not going to wiggle across the sand like a pathetic _worm_.

With a put-upon sigh, Zoro squats down and hauls Sanji over his shoulder. At least the algae-head doesn’t grab at his wound, but it still knocks the wind out of Sanji with an indignant squawk. Zoro throws him down in the shallows with the same lack of consideration, and Sanji resists the urge to yank the human down into the water with him by the rope kept tight in the man’s hands.

As it is, Sanji just shuffles into a slightly deeper pocket, until the water covers his entire tail and he can duck his head under to cool himself. He feels better immediately, even though the salt stings in his wounds and a small amount of blood begins to seep through the bandage.

The algae-head jerks on the rope, and glares at him.

“What?” Sanji snaps.

“This is stupid,” Zoro grumbles, and just like that, Sanji gets thrown back over his shoulder.

“Hey!” Sanji barks. It’s not enough time, he’ll dry out right away again -

“I’m not gonna sit around watching you soak,” the algae-head says, effortlessly striding down the beach despite Sanji’s struggling. “Waste of my time.”

Bending his tail too far sends a shock of pain along his side, so Sanji stops fighting and hopes that Zoro won’t drop him. He can’t see where they’re going. The human smells of sweat and dirt and metal, heavy and unpleasant. Sanji can already feel the sun renewing its attack on his skin.

Zoro carries him into the shade of the mangroves, threading along the edge of where the trees leave the island’s soil and grow into the ocean itself. The shade is almost as much of a relief as the ocean, the trees shielding them from the direct sunlight and much of the heat.

There’s another rudimentary shack wedged in at the edge of the water, between several of the largest trees. This one has three walls and a few planks of flooring, and a net full of ratty blankets hanging next to a storm lantern in one corner. Zoro whacks Sanji’s tail against the doorway on the way in, even though said doorway is an entire open side and more than wide enough to pass through safely.

“This should work,” the man mutters, dumping Sanji onto the floor and tying the rope around the trunk of a tree that seems to be partially serving as a support for the front corner of the shack. It’s growing half in the water, the ocean lapping at its exposed roots only a few steps from the entrance, so Sanji assumes it must be close to high tide. Otherwise this would be a stupid place to build any kind of structure.

More importantly, the rope is long enough that Sanji should be able to reach the sea, even when the tide is mostly out; this area has narrow intertidal zones. He eyes Zoro, and finds the human watching him in return.

Sanji knows he looks pathetic. He hopes he looks pathetic and commiserable, or at least pathetic and harmless.

The swordsman comes around behind him again, and actually does untie the rope this time. Sanji doesn’t even feel hope over the confusion, and it’s just as well, because the algae-head only jerks his arms around and starts binding Sanji’s wrists in front of him this time.

“Careful,” Sanji pleads, the entreatment slipping out before he can think better of it. It’s already a miracle that his hands haven’t been damaged. Zoro could so easily tie the ropes too tight, cut off his circulation or pinch a nerve, and ruin them forever. “My hands -”

“You can drag yourself to the water like this, right?” The human interrupts, making glancing eye contact as he finishes the binding, sliding a finger beneath the ropes in a brusque circle. It makes Sanji catch his breath, both the shocking consideration of the gesture and the unfamiliar feeling of the swordsman’s calloused hands against the delicate skin of his wrists.

He holds that breath and nods, wondering if he should promise not to make a break for it. There’s no way he can swim far like this, not fast enough to escape.

“Then I’m going to take a look at that,” Zoro says, pointing to Sanji’s injuries before turning to rummage a bag of supplies out of the net in the corner, “and then I’m going to take a nap, and if you make any trouble, I’ll skewer the rest of you for Luffy to eat when he gets back.”

Awkwardly lowering himself to the gritty floor, Sanji tries to find a position that will put the bite in easy reach without jarring the wreck of his dorsal fin, and still allow him to keep an eye on whatever the human is doing. He doesn’t feel safe, particularly, but he’s less likely to thrash away on instinct and get himself killed if he can watch.

His tail stretches across most of the shabby room, the deep blue and silver countershading dull with grime. The bright gold stripe along his lateral line is barely even visible. After the careless way the humans have been handling him, it’s fortunate that he bends much more easily than a normal sailfish, even if his proportionally longer length is cramped in here. His sharply forked caudal fin is scraping the far wall at an uncomfortable angle, and Sanji is worried that the long pelvic fins at his hips will be the next thing to tear.

Sure enough, the swordsman kneels on one of them as he gets close to Sanji, grinding it against the rough planks of the floor. He shifts off of it almost immediately, but Sanji can see a split in one of the membranes.

“This wasn’t a thresher shark,” the algae head rumbles, laying a hand alarmingly close to the wound Niji inflicted, where the end of the slash stretches beyond the bandages on the mako’s bite. 

“Not your average thresher shark,” Sanji mutters. He wants to move his tail away but there’s no point, it will only make the swordsman more suspicious of him, and Sanji is nowhere near fast enough to escape from him on land. Even without this.

Zoro’s hand presses down harder, expression cold. “Don’t talk back to me.”

Hissing, Sanji lowers his upper body and stares at the floor. He doesn’t like the look of the human’s tan skin beside the red-edged gash in his scales. It’s too reminiscent of watching the old geezer’s employees gut fish.

Still, when the algae-head starts tugging at the bandages, Sanji looks back up. He needs to know how bad it really is.

“Usopp poured a fuck-ton of his liquid stitches in here,” the swordsman mutters. “That shit’s worse than glue, all the bandages are stuck.”

It hurts like Zoro is pulling his skin off, but Sanji grits his teeth and barely lets out a whimper as the man wrangles the bandages away. Near the end Zoro pulls out that horribly familiar knife, and holds Sanji’s tail down in a harsh grip as he cuts away a few smaller chunks that are more firmly stuck to the bandages than to Sanji’s flayed skin.

Sanji collapses at that, forehead thunking against the filthy floor as dizziness sweeps through him. He can hear himself panting, an almost constant whine, and an impatient noise from the human.

“At least you didn’t bleed out,” the man snaps. “There’s a hole the size of my head in your side, you’re lucky to be alive, blondie.”

The algae-head is exaggerating, but only barely. When Sanji can lift his head to get a look at his exposed tail, he can see that a wide area not far below his hips is a ravaged, gaping crater, coated in a curiously matte gunk. It makes the pink of raw muscle less appalling, but the lack of fresh blood makes the damage all too obvious. The wound isn’t terribly deep, but he might never be able to swim the same after this, assuming he even escapes.

Next to that, it’s hardly worth thinking about Niji’s slash. Its edges are clean, the cut deep but uncomplicated. A few stitches will fix it right up, and that seems to be where the swordsman is planning to start, as he pulls out a heavy needle and thread.

“Does eating mermaid really make you immortal?” Zoro asks, squeezing the sides of the wound together.

“Does it matter?” Sanji bitterly counters. At least the conversation will distract him from the pain. “Of course it doesn’t, idiot. But you’d be able to sell pieces of me to enough people who believe it does.”

“It matters because the world isn’t prepared for Luffy to live forever,” the algae-head mutters. He glances at Sanji’s face for a moment, meeting his eyes just long enough for Sanji to see doubt in his expression, and goes back to unceremoniously tacking his tail back together. “I know people will believe whatever they want.”

The stitches are thick and ugly, crooked and unevenly spaced. Sanji could almost cry from relief as Zoro ties off the top half of the slash, but if he starts crying now he won’t be able to stop. “Humans believe a lot of stupid stuff.”

“I’m sure your lot do too,” the swordsman retorts, tugging the first stitch in the lower section of slash a little harder than necessary. “You sure mouth off a lot for a guy with my hand in his side.”

Sanji clicks his teeth shut. It’s disturbingly easy to bicker with this man, and a terrible time to do it. Watching Zoro finish that line of stitches in silence, he wonders what he could say to improve the human’s opinion of him. Getting on his good side would be a big step in ensuring that Sanji doesn’t end up butchered and eaten.

Niji’s handiwork dealt with, Zoro moves on to the bite proper. He pins a stitch or two in spots where the edges are especially torn, but no amount of thread will make Sanji’s skin meet over the main body of the wound. Setting the needle aside, the algae-head picks up a small glass jar of opaque gel.

“What is that?” Sanji asks, as the man uses a bit of discarded bandage to scoop out some of the gel. It has an astringent smell and doesn’t reflect light the way a liquid should.

“Usopp calls it liquid stitches,” Zoro answers. “Keeps blood in, keeps dirt out. Kills the pain a little, too. Dunno if it’s really safe to use all up inside like this, but you’re not gonna complain.”

The algae-head goes to swab the stuff around inside the bite, and Sanji has to look away again, suppressing a gag. “He makes it himself? What’s in it?”

“Nothing I let him tell me about,” Zoro grunts, jabbing his fingers into a particularly deep area of the wound. Sanji lets out a sob, but the man doesn’t ease up. “Used to sting like a bitch, but Usopp took the recipe to Law and they worked something out.”

Considering the pain of having the algae-head digging around in there, Sanji doesn’t think he would have so much as felt a bit of medical sting. He does his best to breathe evenly and keep his tail still, with Zoro’s free hand a heavy reminder pinning him down.

Sanji watches the muscles shift in the swordsman’s thighs as he adjusts his balance, leaning more of his weight onto Sanji’s tail. Sanji doesn’t have a lot to compare to, but he thinks this human is particularly heavy. Or maybe Sanji just can’t handle the unfamiliar pressure, stuck between the man’s rough hands and the hard floor.

Finally Zoro sits back, one hand resting beside the bite like a warning, as if Sanji could or even would try to get away. Should, maybe, but there’s no chance as the algae-head untangles some bandages and grabs Sanji’s tail near the end, hauling him into an entirely undignified position flat on his back, with his caudal fin looped up - down? - by his head and his hips barely touching the floor.

“Hold still,” Zoro directs, as if this pose is easy and convenient for anyone except him, as the swordsman loops bandages around his tail. Any other day, Sanji would bludgeon the man with it, but today he braces his shoulders against the planks and trembles from the strain on overworked muscles. 

He can feel his dorsal fin scraping, unable to fold correctly. Hopefully the human doesn’t go for that injury next - Sanji doesn’t trust him to fix something so delicate. He’ll have to splint the broken spines himself somehow, find a way to immobilize the torn membranes…

Tipping him back down with a thud, Zoro ties off the last section of bandage and releases a deep sigh. “There,” the human mutters. “Now the witch can’t say shit about damaging merchandise, or whatever the fuck she’d come up with.”

Sanji clenches his jaw and lies still until he knows the first thing out of his mouth won’t be vitriol. Being called _merchandise_ makes his skin crawl, but he’s not ungrateful for the medical attention, no matter how callous.

“This isn’t really waterproof,” Zoro says, tapping the bandaging. “Dunno what will happen if you soak Usopp’s goop too long, but that’s your problem now. Go ahead if you want, I’m gonna sleep.”

A dismissive wave at the ocean lapping through the mangroves, a last not-exactly-harsh whack at Sanji’s tail, and the swordsman levers himself up. Without so much as bothering to take a blanket out of that net in the corner, he settles down against the far wall and closes his eye.

Sanji feels light-headed and weak, but he gets his trembling arms under himself and drags his way out of the shack before the swordsman can change his mind. It’s hard with his wrists tied, but he doesn’t have to get far.

The water is clear around the sweeping prop roots, full of tiny fish and crabs that scatter as Sanji gets close. A narrow channel between the trees suggests that the humans bring a boat this way sometimes, and Sanji can see the sparkling expanse of the ocean through the end of the tunnel. Otherwise the mangroves are thick in every direction, creating a quiet and secretive shelter.

Splashing awkwardly into the shallows, Sanji looks back to find Zoro watching him, gaze sharp despite his relaxed posture. Raising his bound hands, Sanji can’t help snapping at him. “Not going anywhere, algae-head!”

The swordsman huffs and closes his eye again, which Sanji supposes is the best he can expect. It seems the human really does intend to sleep.

Conscious of his bandages, Sanji scoots as deep as he can with the rope and completely submerges himself just long enough to soothe the irritated skin, then finds a bit of convenient root to prop his tail up on. He lets his head fall into the water, hair drifting in the mild current, and breathes through his gills for the first time in hours.

They’re dry, the salt feeling harsh as it passes through. It stings in all the various scrapes he’s acquired, too. The mangrove roots dig into his skin and he can’t say he’s comfortable, but no amount of petty discomfort can ruin the relief of returning to the ocean. Compared to circling sharks and stinging jellyfish, sand and heat and careless violence, this is paradise.

It’s a chance to plan. That’s what Sanji is good at, thinking and planning and clever escapes. Hiding from his brothers, avoiding his father, sneaking away to visit the old geezer. It should be easy to apply that strength to getting out of this predicament.

To survive a kidnapping, it’s crucial to make your captor understand that you’re a full person. Often in a less literal sense than this, but that only makes the first hurdle more straightforward, if more difficult. If he can get Zoro on his side, Sanji has a much better chance of winning over the other humans. 

Making conversation hasn’t helped. Sanji can’t help it that the algae-head is a moron, and utterly infuriating. Anyone would fight with the man. Trying to hold a longer conversation with him is more likely to get Sanji killed on the spot than improve their relationship, but he doesn’t know of too many other ways to quickly build rapport.

He could offer sex. It’s extreme, but so is this situation, and it’s nothing compared to being eaten. Sanji runs a hand down his front, considering his options. It’s not uncommon for male mers to fuck each other in the genital slits that conceal their cocks. Sanji hasn’t done that before, but it’s supposed to be less demanding than other kinds of penetrative sex. As he strokes over the area, his scales begin to part as the tight muscles relax, and Sanji can feel a hint of warm moisture. Of course, the brutish human might be put off by Sanji’s dick, which would outweigh the benefits of that natural slick.

Moving his hand lower, Sanji passes over a second almost imperceptible divot, and spreads those first beads of liquid over his anus. People do it that way all the time, humans included, but Sanji has never liked the idea of it much. Besides, this hole is tiny, forbiddingly tight, and he doesn’t think the swordsman has the patience to use him this way without hurting him. Even if Sanji prepared for it beforehand, it feels much more dangerous.

With a bitter sigh, Sanji slides his fingers back up to that spot between the other two. This is the best option, the most novel, the least likely to make the algae-head recoil in disgust from Sanji’s foreign-looking merman cock or refuse on the basis of being uninteresting in men.

Sanji has always hated this part of his body. It’s only another thing for his brothers to mock him about, as if they need more ammunition. His unusual flexibility is enough reminder of his seahorse mother. He doesn’t want or need the egg-brooding pouch, has never considered using it for sex or worse, breeding.

Ironic, if he can save his own life by the very actions his brothers have always enjoyed speculating about, all the degrading things they’ve said about him. If he can earn the kind of rapport he needs to survive by letting Zoro stick his dick in this humiliatingly fuckable organ, maybe all the demeaning suggestions will be worth it.

He’s loosening up at just the thought and coaxing touch, liquid warmth seeping out around his fingers. If he has to, he can do this. Anything is better than being chopped up and sold as an exotic snake-oil meal.

Of course, this all depends on the algae-head. He might not find Sanji appealing at all. Maybe Zoro is the type of human who would never dream of touching a _monster_ that way, and would turn on Sanji with even more violence for offering it. Maybe he would only be interested in Sanji’s human-looking half. Sanji will have to be careful in feeling him out.

~o~O~o~

Sanji gets a few uninterrupted hours in the water, enough that he feels almost collected. Even the wounds in his tail don’t hurt as badly, now that no one is prodding at them. He drapes himself over the mangrove roots, occasionally rotating to dip the exposed parts of his tail, but here in the shade he’s at much less risk of drying out. Keeping the bandages mostly-dry isn’t a hardship.

The sun is dipping low over the ocean by the time the algae-head stirs, stretching his arms over his head with a deep groan. Sanji, who has been floating idly with his own arms outstretched to make the most of the rope, jerks in place, trying not to splash and draw attention to himself.

He needs a moment. Presentation is everything, and this position makes him look more like he’s strung up in a human fishmarket than anything else. The shitty geezer would laugh at him. 

As quietly as possible, Sanji tries to find a pose that will be appealing without looking like an obvious seduction. He can already tell that the swordsman won’t respond well to manipulation, so Sanji will have to be subtle. It’s his life on the line. Literally.

He settles for lounging in the shallows closer to the shack, one hip and bandages out of the water but angled away so the wound isn’t immediately visible. He tucks his hands under himself and tries to make sure his pectoral fins are lying straight, lets the sharp curve of his caudal fin break the surface a little deeper in, brushes his fingers through his hair as well as he can to make it frame his face, bites his lip to bring out a flush. Holding his shoulders to best emphasize his collarbones and the dip of his throat, Sanji gazes up through his eyelashes at the human in the shack.

The effort is wasted. Zoro stands, stretches again, yawns, and eyes Sanji with a halfhearted glare before stomping around the back of the shack. When he comes back he only gives an equally unenthused sigh. “What do you eat?”

“Normal food,” Sanji snaps. What, does the idiot think he’s actually some kind of primitive fish?

“How should I know?” Zoro mutters, rolling his single eye. “You sure didn’t react well to Luffy earlier, thought maybe your kind don’t eat fish.”

“We don’t eat _each other_ ,” Sanji screeches, pushing himself up as much as he can. “Of course we eat _fish_.”

The swordsman eyes the bite, raising an eyebrow. “Never?”

“No,” Sanji retorts, sullen. Seems like the guy suspects not all of his injuries are from actual sharks, and it’s not quite true that mers never eat each other, but that’s not a conversation Sanji wants to get into. “Barbarian.”

“Well, good, because we’ve got fish and not much else,” the algae head says, shooting him a dirty look.

“Surprised you’re bothering to feed me,” Sanji mutters. He regrets it almost immediately, disturbed by the idea of missing meals until he manages to escape from these people. He’d managed not to think about the possibility until now, but the threat of it gives him a chill.

“I’m not _torturing_ you,” Zoro says, affronted.

Sanji sneers at him, smacking his tail against the surface of the water. That’s… true, but barely. This entire experience has been one of the worst of Sanji’s life. Kind of pathetic, that he can’t say it’s the _absolute_ worst.

“Nami better hurry the fuck up to get here already,” Zoro says under his breath, and starts stacking wood in a ring of stones that have obviously been used this way before.

It’s a mediocre fire, once the algae-head gets it lit and goes to pull a much smaller fish-trap out of the mangroves not far from Sanji. A random selection of fish flop around inside, and Sanji starts dragging himself out of the water when it becomes clear that Zoro intends to kill and clean them right there. 

“Where are you going?” the man asks suspiciously. He punctuates the question with a sharp thwack of the hilt of his knife against the first fish’s skull, which, at least he’s not the type of human who doesn’t bother to stun a fish before gutting it, but Sanji still flinches.

“Don’t feel like bathing in fish guts, algae-head,” he snaps.

Zoro grunts, watching Sanji struggle out of the shallows for a few seconds, and goes back to cleaning the fish without further comment. It’s humiliating to have the swordsman watch him like this - unable to get decent leverage with his hands tied, unable to move his tail to help without agitating the wounds - but there’s no other choice. If they’re going to eat this fish, Sanji wants it to be better than half charred and half raw, which is how it will turn out with a fire like that.

Luckily, there’s a stash of firewood against the side of the shack closest to the fire pit. Sanji can reach both without dragging himself over too much dirt. It’s just a pile of mangrove branches and driftwood, but he’ll be able to fix up the fire.

“Now what are you up to?” the algae-head demands, hefting his knife. A clump of blood and scales slide off the blade to splatter on the ground.

Sanji shoves himself upright and brandishes a stick. “Fixing your shitty fire. You’ll never get fish to roast properly over something like this, and I don’t see a pan or anything more sophisticated anywhere in this shed.”

“What would you know about it?” Zoro growls. 

“More than you, apparently,” Sanji retorts. 

“Where did a mer learn about fire?”

“None of your business!”

The swordsman comes over, half a dozen random fish skewered on sticks in his hands. Apparently the man will eat anything; Sanji wouldn’t look twice at some of the fish he caught. Not all species taste good. Of course, he won’t refuse any of it, in this situation.

“Whatever,” Zoro mutters, staking the fish around the edge of the fire pit. Sanji clicks his tongue in disdain, wobbling on his tail as he reaches to move them farther back. He almost pitches into the fire himself, but the algae-head catches him, roughly shoving Sanji back upright. “Watch it.”

It’s hard to resist the urge to brush the man’s touch off his skin. Sanji grits his teeth and nods, the closest to thanks he can bring himself to offer. Judging by the careless way Zoro dismisses him, Sanji has a long way to go if he wants to entice the human.

Counter to his halfhearted plans, Sanji is only relieved by the silence as they wait for the fish to roast. It’s tense but not antagonistic, and gives him a chance to reassess the swordsman. If Sanji can find something desirable, or even abstractly attractive, about the man, it will be easier to move forward with trying to seduce him.

Zoro has that strange, sun-kissed darkness to his skin that is so very human. It’s different as can be from Sanji’s liquid pale. The swordsman is riddled with scars, not least the one struck through his eye - Sanji can see the edge of what must be a massive disfiguration beginning at the neckline of his shirt, and there’s no point in trying to list all the marks scattered across the man’s arms. That warm tone of his skin only makes the imperfections more obvious.

He’s… not _un_ attractive. Sanji can appreciate the exotic, even in the form of a scowling human fisherman, and Zoro is unlike anyone Sanji has ever gotten familiar with. He just doesn’t want to get any closer to the algae-head’s heavily muscled arms and cold expression. Imagining the man’s rough, dry hands reaching for him sends a shiver down Sanji’s spine.

The wind shifts at the same moment Zoro raises his remaining eye to look at him. Sanji blinks, feels the inner lids of his own eyes slide down and knows the swordsman saw the inhuman detail, opens his mouth to snap something - and the sea breeze buffets him right in the face with the scent of roasting fish.

It’s too much, too soon after watching that other human eat… Sanji forces the thought away, trying not to gag. The smell is horribly similar, though, and even though there’s nothing else to eat, Sanji is suddenly unsure if he’ll be able to eat _this_.

“What’s wrong with -” the swordsman starts, and Sanji can see the moment realization cuts through the irritation. Zoro’s gaze flickers down Sanji’s tail and back, lingering on his rapidly blinking eyes and forced breathing.

“Nothing,” Sanji chokes out, and the man raises one eyebrow, reaching out to turn the fish.

“Sure,” Zoro says, “but you’re gonna have to eat, if you want to survive. An injury like that takes it out of you.”

“I know,” Sanji snaps. The tip of his tail thrashes against the ground, tearing up old leaf matter. Zoro watches the movement with cautious attention, and Sanji can feel his panic ratchet up a notch. He’s doing a terrible job of acting familiar, of acting appealing or human. He has to eat. Sharing a meal, even one so rudimentary as this, is the purest kind of companionship. It should be an easy step toward becoming a person to the swordsman, instead of a dangerous monster, and here Sanji is, unable to even catch his breath. The air feels so hot.

With a frustrated sigh, Zoro levers himself up off the ground and comes around the fire toward Sanji. This time, the dry touch of his hands is a welcome distraction as he shakes Sanji by the shoulder.

“Quit freaking out,” the algae-head grumbles.

Not exactly dripping with compassion, but it’s enough for Sanji to focus. The swordsman has such a strong grip - it’s obvious that most of his strength is in his upper body, although he doesn’t have the stick-thin legs that look so oddly unbalanced on so many humans. Nothing like the power of Sanji’s tail, but not bad.

Sanji stares into the human’s eye, grey like metal, like the man’s swords, and assumes he’s blown his chances. He’s surely too much trouble, and Zoro will simply tell his friends that the wounds to his tail killed him, what a shame they won’t be able to sell him off as an aquarium specimen or exotic steaks - 

“What did I just say,” the man mutters, giving Sanji another shake.

“I’m not freaking out,” Sanji instinctively argues.

Zoro sighs again. It’s a well-practiced sound. “Are you going to be able to eat this or not?”

“Of course I am!”

The algae-head reaches for one of the fish, pushing it into Sanji’s hands. “Then do it,” he challenges, grabbing another for himself.

Biting into the fish is easy. Chewing is hard, as the flavor kicks in and Sanji wonders if his own flesh tasted the same, but he meets the human’s irritated gaze and swallows anyway. Zoro grunts and looks away, digging into his own meal.

It’s far from the best thing Sanji has ever eaten, far even from being the best spit-roasted fish he’s ever cooked. But right now it feels like a victory, as he sits in uneasy silence beside the inscrutable human swordsman.

Sanji finishes his fish, feeling a bit too queasy to reach for another, even though he’s not full yet. Zoro glances at him, but doesn’t say anything as Sanji draws his bound hands back into his lap. 

His scales still feel cool and smooth to the touch, but Sanji would prefer to get back in the water sooner rather than later. Is that allowed? The sun is almost fully set by now, only a glimmer of light still reflecting through the trees. 

“You done?” the swordsman asks. His expression doesn’t look so cold in the firelight. Sanji nods, and Zoro tosses his skewer into the fire. “Okay. Uh, you sleep in the water?”

Scowling, Sanji bites back a sarcastic retort, and keeps his answer short. “Where else, algae-head?”

Well. He tried to bite back the sarcasm.

“How would I know?” Zoro snaps. “Whatever. Let me look at that, and then you can get out of my sight for a few hours.”

Sanji sneers, but leans back to let the swordsman run a hand over his bandages. The algae-head doesn’t try to redo them, apparently satisfied that they aren’t too wet or disturbed by Sanji dragging himself around.

He checks the rope around Sanji’s wrists, too. It’s waterlogged, tighter than ever, and Zoro frowns a little as he takes a firmer grip on Sanji’s forearm to slide a finger under the binding.

“I’m not going anywhere,” Sanji reminds him.

“Guess not,” Zoro mutters, dropping his hand to the joining between Sanji’s skin and scales. He lets go of Sanji’s arm and sits back, fingers sliding aimlessly over the uppermost section of Sanij’s tail as he moves. Right where Sanji was touching himself earlier, and he can’t help but flinch.

“You seem stressed,” Sanji says, before Zoro can accuse him of the same.

“Just don’t try anything,” the algae-head snaps, frowning deeper. 

“Maybe I could help with that?” Sanji presses. It’s difficult to say. He moves his bound hands to the ground and leans in a little, looking up through his lashes at the swordsman. Is this a good time? Probably not, but Zoro has been considerate of him throughout the meal, and Sanji has to try.

“Yeah, by behaving yourself,” Zoro retorts, getting to his feet and glaring down at Sanji. “I don’t want to hear from you until morning.”

The human strides off, disappearing into the trees. Sanji keeps still and watches until the sounds of snapping twigs and dry leaves fade. Outside of the ring of firelight, the darkness is nearly impenetrable.

That didn’t go particularly well, but it seems like the swordsman didn’t pick up on the offer, rather than rejecting him outright. Once again Sanji is more relieved than anything, the accidental brush of Zoro’s fingers burning in his mind.

Sanji stays by the fire for a few more minutes. It’s burning down fast, without anyone feeding it, and Sanji can’t help making a few half-formed comparisons to his own situation. Melodramatic, the shitty geezer has called him, but the old man has never met Sanji’s family. He has a good excuse to be given to melancholy and pessimism.

Watching the embers dim to coals, Sanji wonders if he’ll ever get to tell the shitty geezer about this. He’d like to tell Zeff that there’s a human out there who’s just as inept at cooking with fire as Sanji used to be. Imagining the old chef knocking sense into Zoro brings a smile to Sanji’s face, even with all the uncertainty pressing down on him.

Dragging himself back to the water, Sanji doesn’t feel as cripplingly weak as before. Funny how much some rest and food can help. He’s getting better at moving without straining his wound, too. By the time he slides into the shallows, Sanji is a little less depressed.

The mangroves are quiet, leaves softly rustling overhead and waves gently lapping through the roots. Something splashes farther in from the channel as Sanji finds a good spot for his tail, letting his head sink beneath the water. The few nighttime sounds are swallowed by the ocean, and Sanji closes his eyes. As he drifts in the mild current, it’s easy to pretend he’s somewhere else.


	3. Medical Attention

When Sanji opens his eyes again, sunlight is filtering through the branches overhead, bringing a languid glow to the shallow water beneath the trees. A few small fish dart away as he shifts, and a puff of silt clouds the water as a crab scurries for cover.

There’s also an unfamiliar sound permeating the water, getting louder as Sanji yawns and stretches. He pops his head above the water, bound hands digging into the silty seabed for balance. 

“- you left it tied up all night?” a new, female voice demands. 

“I told you I bandaged him up,” Zoro protests, amidst the rustle and snapping of footsteps coming closer. “What else was I supposed to do, witch?”

The lady scoffs, and Zoro makes an outraged sound. Sanji scrambles to the edge of the water, levering himself up and trying to make his hair presentable.

“He said he sleeps in the water!”

“You’re an idiot,” the lady grumbles.

An extra enthusiastic snapping noise, and a familiar laugh. “Shishishi! Where else would a fish sleep?”

Bandages, mostly dry. Hair, smooth and untangled over half his face. Tail, artfully curled, scales shining in the dappled light. Fins, lying as neatly as possible, although his dorsal fin in particular is still a mess. Sanji puts on his most charming smile and once again hopes he looks pretty, and appealing, and worth keeping alive.

The humans crash out of the trees, both of the kids back from yesterday along with Zoro and the new, unfamiliar lady. Luffy hops right over to Sanji, dragging Usopp by the arm, but the lady stops at the corner of the shack, with a pensive look on her face. She’s beautiful, all luxurious curves and flowing orange hair, but now isn’t the time to be distracted by that.

“What’s it like, sleeping underwater?” Luffy asks, poking at Sanji’s long pelvic fin. Usopp stumbles to a halt at the edge of the water, looking guilty.

“Oh, for fuck’s sake,” Zoro mutters, pulling Luffy back by the collar of his vest. “At least let Nami get a look at him.”

Luffy’s feet catch in the rope, yanking Sanji down into the dirt as his hands are pulled out from under him. Propping himself up on his elbows as the kid untangles his sandals, Sanji snarls at the swordsman.

“Watch it, algae-head!”

“Why are you yelling at me?” Zoro demands, waving a hand at Luffy.

“You’re the one jerking people around, so just -”

Nami sighs, and Sanji bites his tongue. What is it about Zoro, why can’t he remember how to keep his temper around the man? Fighting like this can’t be good for Nami’s opinion of him.

“Yeah, I can’t do it,” the woman says, glaring at Sanji and Zoro. “Fuck, we could’ve made so much money.”

“Oh thank god,” Usopp whimpers. Her glare turns on him.

Somehow Sanji isn’t so relieved. Just because they’re not going to sell him doesn’t mean they won’t still kill him. And honestly, he’s not sure if he’ll be able to swim well enough to survive on his own until he heals, if they decide to throw him back in the ocean.

“I mean, come on,” Usopp squeaks, raising his hands in a placating gesture. “Turtles are one thing, but I’m pretty sure mermaids count as people.”

“Does that make Luffy a cannibal?” Zoro asks under his breath.

Nami rolls her eyes, coming over to crouch beside Sanji. “I’m Nami. What’s your name again? These idiots aren’t reliable at all.”

“It’s Sanji, mellorine!” he chirps. “If I may, it’s an unparallelled joy to meet a lady as lovely as yourself, even in these circumstances -”

Luffy bursts out laughing, and even Usopp snorts. Nami whips a glare at both of them, and Zoro is just looming behind her with a horrified expression.

“Nami isn’t a lady,” Luffy snickers. “She’s a thief!”

“I’m a cartographer, you imbecile,” Nami snaps, forcefully enough that it scares a more respectful look of fear onto Usopp’s face.

“Still far from a lady,” Zoro mutters, and yelps when she whacks him across the knees.

“Would it kill you to learn some manners?” Nami huffs. “Well, Sanji-kun, I’m sorry we had to meet this way, but it’s all just business, you know?”

Sanji nods carefully. What that means for him still isn’t clear.

“Maybe we should get a different business,” Usopp comments.

“Not if you want a ship,” Nami retorts.

“I want a ship!” Luffy exclaims. Everyone rolls their eyes.

“Gotta break some eggs to make an omelet,” she tells them, shooting Sanji an apologetic glance. “You know Franky’s work won’t come cheap. We’re a few days behind schedule now, so I expect you lot to work extra hard!”

“Omelet?” Luffy says, hopeful expression dripping with drool.

“As if it matters how long we’re taking,” Zoro grumbles. “Nobody agreed to your schedule.”

“You obviously have no idea how much money we’re talking about! Cash doesn’t grow on _trees_ , idiot, and unless you’ve got a pile of gold you haven’t told me about -”

“You know I don’t!”

“I do,” Sanji blurts out. He didn’t think it would be this easy.

“So we have to _work_! Idiot - wait, Sanji-kun, what did you just say?!”

“Gold,” Sanji says, shrinking back a little under Nami’s intense stare. “Not - I mean, I don’t think it’s enough to buy a ship -” not that he has any idea how much a human ship costs, and why would he even _say_ that, “- but there’s a sunken ship, not far from here. None of the treasure hunters have ever found it.”

“A shipwreck with treasure?” Nami demands. Zoro sighs, and Luffy wanders away, picking at his nose.

“Yeah, I’ve explored it a few times,” Sanji explains. “It’s a strange-looking ship, really old. There isn’t much left inside, but part of the hull is full of treasure. Heavy, gold stuff. Mers don’t have any use for gold, and like I said, human scavengers have never gotten near it.”

“Can you lead us there?”

Sanji barely gets to nod his assent before the woman throws her arms around his neck with a cheer. “Sunken treasure! Wow, Sanji-kun, I take it back! I’m not sorry at all, this is the best luck we’ve ever had!”

“Careful,” Zoro growls, laying a hand on her shoulder and leaning over Sanji with a menacing frown.

“Oh, shut up,” Nami says, shifting back and giving Sanji a critical once-over. Her eyes linger on the bandages around his tail, and the reddened skin of his wrists. “We should probably get Law to look at him.”

“We’re gonna go see Torao? Yahoo!”

“You want to bring him back to the island?” Zoro gapes.

Nami shrugs. “Sooner he’s better, sooner I get the treasure. Now, let’s get a move on.”

Sanji looks between them with trepidation as Nami gets to her feet, waving Usopp over. She points him back through the trees and shoves Luffy after, threatening to withhold his lunch if the two of them don’t have their boat ready to go right away, and herds them toward the beach.

“You got him in here, right?” She asks Zoro, turning back with a dismissive wave. “C’mon, bring him back to the boat, let’s go.”

Sanji meets Zoro’s eyes and shivers in apprehension. He can’t help it, but it’s somewhat reassuring to see Zoro looking back just as uneasily.

The swordsman straightens up, steps closer, pauses. Squats down again, this time so close that Sanji can see all the imperfections on his skin, and reaches out for him. Stops. Grimaces, glancing away with a huff. Sanji realizes that he’s holding his breath, and forces himself to let it out naturally. The damn algae-head carried him here earlier, but it’s so much more awkward now that they’ve talked a little.

“Give me your hands,” the human demands, fingers tangled with Sanji’s as he picks at the rope around his wrists. Sanji focuses on the rough calluses and scattered scars instead of the _knife_ , once Zoro gives up on untying the salt-encrusted knot and cuts it instead.

The steel is cold against his skin, and Sanji can’t help a shiver of relief when the swordsman moves the knife away, rope falling abandoned to the ground. Scoffing, Zoro still gives Sanji a moment to run his fingers along his wrists, soothing the faint abrasions.

“Hold on,” Zoro finally mutters, sliding one hand along Sanji’s ribs to grab him under the arm, and levering the other under his tail. The human stands, swinging Sanji into the air, and Sanji reflexively slings his arms around Zoro’s neck.

Gasping, Sanji clings tighter as the swordsman hefts his tail to get a better grip. The man’s skin is very warm. Dry.

“Stop squirming,” Zoro complains. 

“You better not drop me,” Sanji threatens, but goes still and tries to hold his tail close, so the swordsman won’t whack him against so many trees this time. He does his best to relax into Zoro’s hold, going so far as to rest his forehead against the man’s collarbone. 

A few branches drag at him as Zoro pushes through the trees. One catches in the split in his pelvic fin, tearing it further, but slips out before the thin membrane can rip all the way to the edge of the fin. Sanji winces at the tug, shifting in Zoro’s arms, and the human grumbles at him.

“Watch where you’re going!” Sanji snaps, digging his nails into the algae-heads shoulder. “I’m going to have enough trouble patching up my fins as it is!” 

The swordsman actually pauses, peering over Sanji’s head to look down the length of his tail. Those fins are long enough to drag on the ground, like this, and Zoro hefts him up a little. “Huh. My bad.”

It’s almost an apology, and Sanji sneaks a glance up at the man. No expression to be seen, from this angle, but Sanji is mollified enough to let it drop. They continue out onto the sunny beach, and he goes back to shielding his eyes against Zoro’s chest. The feeling of bright sun on his scales and the scent of smoke still clinging to the swordsman’s skin are strangely harmonious, and feel less threatening than before.

Blinking against the sunlight, Sanji looks out over the beach toward the sound of yelling. Nami is shouting at Luffy as the boy rolls around in the sand. Beyond them, Usopp seems to be the only one trying to make their boat ready to go.

“Where do you want him?” Zoro asks as they approach, completely ignoring the commotion and jerking his chin at Sanji.

Nami looks up from Luffy and pauses, calculating. She waves them to the front of the boat and Sanji hangs on for dear life as Zoro jumps aboard.

“Don’t be such a coward,” Zoro sighs, reaching up to pry one of Sanji’s hands away from his neck. He’s supporting all of Sanji’s weight on one arm, the muscle-bound freak. Sanji lets go before the human can snap his wrist and stares at him reproachfully, surprised when the swordsman drops his gaze with a flash of embarrassment before dumping Sanji to the floor.

“Ouch,” Sanji complains. “Hey, algae-head, I’m helping you now, shouldn’t you be nicer to me?” 

That said, the swordsman did drop him at an angle that kept the wounded portion of his tail from hitting anything, so it could have been much worse. Come to think of it, no amount of luck would have stopped Zoro from putting his fingers in the injury if he wasn’t watching out for it; the man was obviously being more careful than he’s letting on.

“You’re still a monster,” Zoro retorts, that moment of openness gone as quickly as it came. “Cause any trouble for us and you’ll go the same way as all the other monsters I cross paths with.”

Sanji struggles to prop himself up, awkward on the rounded bottom of the boat, and scowls up at Zoro. The swordsman only crosses his arms over his broad chest and frowns back, balance shifting naturally as the waves rock the little boat against the sand. Somewhere out of sight, Nami is still howling at Luffy.

Moving one hand to Zoro’s calf instead of the damp wood, Sanji tries to soften his expression. Zoro’s leg jerks in his grip but he doesn’t pull away, so Sanji slides his hand up a little higher and smooths his fingers through the creased fabric at the back of the human’s knee. He blinks, slowly, knowing his lashes will lie stark against his pale skin as he does it, and parts his lips just slightly.

“So suspicious,” Sanji says, forcing his voice to be lilting instead of bitter. “Haven’t I been good so far?”

Now Zoro pulls his leg away, startling like he’s just woken up. “No.”

“No!?” Sanji squawks, hurriedly catching himself on the edge of a seat.

“Major pain in my ass,” Zoro mutters. He turns away to mess with some rope, adjusting with that same easy flow as Luffy leaps into the boat.

Sanji grits his teeth and holds on tighter as the boat rolls. It’s half-grounded and still feels like a leaf in a whirlpool. How these humans feel safe riding this flimsy thing across the depths of the ocean, he will never understand.

Nami shoos Usopp aboard and slaps Zoro’s shoulder, pointing out at the beach. “Give us a push here, big guy.”

“Next time don’t let Luffy drive us into the sand,” Zoro grumbles, but jumps into the shallows and heaves the boat out into deeper water. Sanji catches his breath a little, watching the muscles move in Zoro’s arms and shoulders.

After that, he’s too wrapped up in enduring the motions of the boat to think about the swordsman. If the human came up to stab him right now, Sanji isn’t sure if he would even notice. He might actually thank him. It’s not even a rough day, but the tiny boat skips across the surface of the ocean, rocking like it will capsize at any moment. Compared to the gentle swell of the waves underwater, this feels like being thrown into a rip tide while blindfolded.

The humans move around the boat as easily as dry land. Luffy skips along the sides with his arms outstretched, laughing like a lunatic; Usopp scurries from side to side fussing with ropes; Zoro hauls at the single sail and barks at the others; and Nami stands by the tiller, directing the madness like the queen she clearly is. Sanji holds on to the edge of the nearest seat with a white-knucked grip and stares at the line where the ocean meets the sky.

By the time their destination comes into sight, the sun is much closer to that mark. They’ve been sailing all day, and Sanji’s initial dismay has transitioned to boredom. Tucked under a spare bit of tarp, he’s safe from the relentless sunlight, and almost comfortable. Even the lurching skips as the boat crests the top of especially high waves are becoming familiar.

The island appearing over the horizon is one of the largest human-inhabited ones in the area. Sanji has swum around the coastline a few times - there’s a city on the south side, cliffs along the eastern coast, pastures west of the city, and mostly forest across the rest, from what he's seen. Seals like to sun themselves along certain quiet sections of the coastline. It’s a nice area, just too many humans around to be safe.

That problem is long past. 

“Woohoo, Torao!” Luffy cheers as they approach.

Sanji watches the sunlight refracting off the water, until the ocean floor rises high enough to see from the surface. Then he watches the changing patterns of the seafloor, trying to remember what the reef shapes they’re passing over look like from below, which patches of thick kelp forest are dominated by seals, and which by sharks.

To his surprise, Nami directs them past the city, staying a good ways farther out from the coast than the fishing boats hoving in for the night, or the large ships moored in the deeper part of the harbor. Instead they skirt around the island to the east, sailing into the shadow of the cliffs.

“We’re not going into town?” Sanji asks, oddly unsettled. He doesn’t want to go to the human city, but the cliffs looming dark over the ocean are hardly welcoming, either.

“Nah, Law’s not a real social guy,” Usopp mutters, fiddling with some ropes nearby.

Scoffing, Nami points them closer to the shore. “You’d end up in some rich guy’s aquarium right away, if we went into town. The kind of money people would start throwing at us, I wouldn’t be able to help myself.”

“Witch,” Zoro grumbles.

The darkness under the cliffs feels a lot more sheltering, after that.

They tie the boat to a rusty metal ring sheltered behind a narrow spur of rock. It’s invisible from the water, and at first Sanji can’t see why they’ve stopped here at all, but as his eyes adjust to the gloom he can see the low entrance to a sea cave, with a bit of floating dock providing a path inside.

Luffy leaps off the boat, shouting, and carelessly runs along the boards, water splashing up with each heavy footfall. The entire structure groans and creaks and he has to duck to get under the cave entrance, but none of it slows the boy.

“Almost high tide,” Nami says, making sure everything in the boat is tied off at a much more sedate pace. “It can be tricky to get in, when the water gets really high.”

Sanji nods, and can’t help thinking how easy it would be for him, if he could swim properly right now. He can’t, so Nami orders Zoro to scoop him up again, and Sanji clings around his neck with embarrassing desperation as the swordsman walks across the shifting bits of dock. Once again, Zoro grips his tail carefully distant from the injuries, and this time, Sanji is paying enough attention to notice the way the human’s hands shift, feeling around for the most gentle hold.

The cave ceiling opens up after a few steps where Zoro has to crouch close to the boards, dragging Sanji’s tail fins in the water, and they enter a narrow tunnel lit with a strange, scattered glow Sanji eventually realizes is some kind of birds’ nests.

“Glow swifts,” Usopp whispers, when he sees Sanji looking. “Kinda like cave swallows, or chimney swifts - oh, you probably don’t know much about birds, do you? They’re bigger than most swifts and still mostly eat bugs, but they’ll eat small bats too, if they can catch them.”

As Zoro creeps along the ledge, Sanji can still hear water lapping below them. It’s too dim to see more than the occasional gleam off the waves, but clearly the ocean flows all the way through the tunnel.

Trying not to move and frustrate the swordsman, Sanji can’t help feeling grateful for the sun-baked warmth still radiating off his skin. The cave is cold, and Zoro grunts when Sanji shivers.

“It’s warmer inside,” Zoro says, squeezing Sanji a little closer. “But come on, wimpy fish, isn’t it cold in the ocean?”

“That’s different!” Sanji hisses, although he’s not quite sure how. Whatever. The clammy air in this dark cave is unpleasantly cold, whereas the chill of the open ocean is refreshing.

It feels like a long way, but within another minute or two Sanji can hear voices - well, one now-familiar voice in particular - chattering, and then light begins to suffuse the tunnel, and suddenly Zoro walks out into a much larger cave. This space is well-lit and pleasantly warm, even with the pool of ocean water lapping at the lowest point of the floor where the narrow tunnel ends.

“See, Torao? We caught a mermaid!” Luffy exclaims, dragging another human over to them.

He’s a little older, taller; short dark hair and a scowling expression to rival Zoro’s, but none of that catches Sanji’s attention nearly as much as the sheer volume of _tattoos_ visible under his open coat. That, and the piercing intensity of his eyes, golden yellow and keenly intelligent.

“I see,” Torao deadpans. “And here I thought even you couldn’t raise hell just by going fishing.”

Nami groans at that, shaking her head.

“Oh ye of little faith,” Usopp mutters.

The man ignores them, and steps closer to where Zoro is holding Sanji. Looking up from such a vulnerable position makes him nervous, but Sanji meets this Torao’s eyes as steadily as he can.

“My name is Trafalgar Law,” he introduces himself, gaze scanning over Sanji in such a way that he can tell Law is cataloging every little thing he sees. “And I assume these four would not have brought you here for no reason, so -”

“Tail,” Zoro grunts, rolling Sanji just enough to force the bandages into easy view. Law draws in a sharp breath. “Sharks, he says.”

“It _was_ sharks,” Sanji snaps, tensing his arms around the swordsman’s neck. Better than hitting him.

Law doesn’t look away from them, gesturing deeper into the cave. “Over here.”

As they move up several rough-carved steps, Sanji can see a few more cave entrances branching off of this one. Now that he’s looking, it should have been obvious, because this cave is empty save for the lights and a thick pile of white fur near one of the other entrances.

Law leads them toward that one, and as he does, the pile of fur shifts, getting to its feet with a rumbling growl. Scrambling to the other side of Zoro, Usopp squeaks in fear, and even Nami gives it a wide berth.

Sanji freezes in Zoro’s arms, unable to tear his eyes from the thing. He doesn’t know much about land animals, but it’s enormous, nearly as tall as Law even standing on all four paws. Its head swings toward them, and as it yawns Sanji gets a terrifying glimpse of its teeth, as long and dangerous as any shark he’s ever seen.

“Bepo!” Luffy cheers, dashing at the creature. Law snags him by the back of his vest, and visions of blood recede from Sanji’s imagination.

“You can feed him later,” Law says, pushing a barely-appeased Luffy through into the next cave. As he follows, he reaches out to scratch behind the creature’s ears. “Good Bepo, go back to sleep.”

“What is that?” Sanji hisses, only realizing that he has a stranglehold on Zoro when the swordsman pries Sanji’s hands away from his neck.

“Bepo,” Zoro grumbles.

“Greater ice bear,” Usopp whispers, peering around Zoro’s shoulder to keep the creature in sight as they pass. “Very intelligent. Very dangerous. Can take out a whole ship of whalers, those guys. Oh, but don’t worry, I, the Great Captain Usopp, have sailed many a season without -”

“He’s harmless,” Zoro sighs, giving Usopp a shove to keep following Nami. “Now stop choking me or I’ll drop you, blondie.”

This cave is smaller than the last, more brightly lit and full of glass and shining metal, noisy with so many people crammed inside. Everything is distracting enough that Sanji yelps when Zoro tries to put him down on a high table covered with white cloth. He isn’t sure what the rest of his expression looks like, but Sanji can feel how wide his eyes are, and Zoro winces when he meets Sanji’s gaze. The swordsman actually seems reluctant to let him down as he pushes Sanji’s hands away and steps back.

“I’m a surgeon,” Law says in a low, soothing voice, pulling a pair of white gloves down over his wrists as he comes close. “Will you let me treat you?”

Sanji nods, staring into Law’s golden eyes and allowing the human to push his shoulder down to the table. Lying on his side like this brings back the memory of Zoro cleaning his wounds, with all the grace of cleaning a dead fish; at least this Law seems to know what he’s doing.

“You’re a marlin of some kind?” Law asks, considering the coloration of his scales.

Blinking in surprise that the human bothered to wonder what kind of fish he is, Sanji raises what he can of his shredded dorsal fin, leaning his chest closer to the tabletop.

“Sailfish, then,” Law wryly corrects. “I’ll look at that after we fix up your tail. These as well,” he adds, running a hand along one of Sanji’s damaged pectoral fins.

With that, the surgeon picks up a gleaming silver scalpel and begins cutting away the bandaging on his tail, and Sanji looks out at the rest of the room. The other humans are clustered a short distance away, Nami holding Luffy back by the arm, and there’s a smaller figure puttering around behind some shelves…

“Why don’t you tell me what happened,” Law says, reclaiming Sanji’s attention.

Sanji gives him the condensed version, leaving the details of his brothers’ cruelty and Zoro’s rough treatment out of it. There’s no reason to get into the terror and desperation he felt. Law’s expression gives nothing away, and his hands are steady and sure as he removes the last of the bandages.

“I’ve seen worse,” he says under his breath, tracing the outer edges of the wound with one feather-light finger. “Chopper, I need a flesh-safe solvent.”

“Right away!” a bright voice chirps, and the little figure Sanji couldn’t get a good look at earlier dashes out across the floor. He still can’t see much more than a flash of pink and brown, until a tiny pair of hooves lift a clear glass vial over the edge of the table.

“Thank you.” Law takes it with no further comment, pouring a small amount into a dish on the silver stand beside him, and Sanji tries to crane his head over the edge of the table without moving.

Zoro catches him looking and frowns, rolling his eye. “Hey Doc, the fish wants an introduction.”

Expecting Law to answer, Sanji is startled to hear the bright voice respond, from somewhere right below the table.

“Shut up! I’m not a doctor yet, hearing that doesn’t make me happy!”

With a poorly hidden smile, Zoro crouches down and opens his arms. “Come here.”

Sanji’s attention is diverted again as Law swabs a bit of the strange liquid into his wound - it’s cold, and stings slightly, but the surgeon’s expression is calm and attentive. When he turns back, Zoro is lifting a furry creature off the floor. 

“This is Chopper,” Zoro says, hefting the child-shaped animal against his hip. It’s wearing little human clothes, including a large pink hat, but it’s covered in brown fur, with tiny hooves instead of hands, and long ears sticking out beneath the hat.

“Tony Tony Chopper!” it announces, grinning happily. “I’m a reindeer, but I ate a devil fruit, and I’m going to be a doctor! Law is teaching me.”

“A local anaesthetic, please,” Law requests, with a hint of a fond smile.

Chopper wiggles out of Zoro’s arms and disappears around one of the shelves, returning with another mysterious vial. Sanji gapes, watching his little tail wag as he returns to Zoro.

“You’re developing an infection,” Law informs him, catching Sanji’s gaze and holding it. “This will numb the area, and then I can remove the dead flesh. Once it’s clean, the wound will heal more easily.”

“Okay,” Sanji croaks. He can’t help remembering Zoro, again, cutting away the ruined chunks of his tail and letting Luffy _eat_ them.

“Don’t watch,” Zoro gruffly orders, distracting him. That seems like a good idea, so Sanji doesn’t, although he wishes he had when Law slices out thin pieces of poisoned flesh without so much as a scalpel. He must be some kind of devil fruit user, too.

Throughout the procedure, Chopper dashes back and forth fetching the medical supplies Law requests. Sometimes Zoro will lift him to a higher shelf, or bring something down for him. The swordsman clearly loves the little reindeer.

“All the other monsters,” Sanji mutters, remembering Zoro’s earlier threat as the swordsman circles around helping Chopper. The guy isn’t as tough as he acts.

He is tough, though. Sanji shouldn’t let one moment of doting affection distract him from that. There’s no denying the scars scattered all over the swordsman, or the effortless way he handles those swords.

No one hears him but Law, who flicks a knowing glance at Sanji between treating the fresh cuts with antiseptic and beginning to re-stitch the wound’s edges with much more professional sutures. “They’re good people.”

Sanji is surprised that he doesn’t disagree. Maybe all the strange medications Law has been swabbing into him have affected his brain.

The surgeon’s odd smile only widens when Sanji stays quiet, and he sends the others out of the room with instructions to set up a tank for Sanji to recuperate in. Only Chopper stays in the room, eventually hopping up on the table to help with the new bandages.

“Let me look at your fin,” Law instructs, after giving Sanji’s tail a last critical examination. Chopper scampers off to bring Sanji a pillow he can lean on as he rolls onto his stomach.

Law isn’t a chatty person. While he straightens Sanji’s fin, splints the broken spines with thin metal bars and tapes the membranes back together, Sanji can hear plenty of the ruckus in the other cave. Splashing, crashing, Usopp screaming, the scrape of claws on stone and a heavy growl.

Chopper sneaks a nervous glance at the entrance, but Law only sighs and shakes his head. The commotion continues.

“Are they… okay?” Sanji eventually asks. It’s the first time since meeting them that he’s felt secure enough to wonder about anyone else. Law’s patient attention has gone a long way toward patching up more than just Sanji’s physical injuries.

“Bepo won’t hurt them,” Law dismisses, steady hands smoothing Sanji’s dorsal fin back down along his spine. “There. Try not to move it too much for a few days. I want to keep you here at least that long, so you shouldn’t need to use it.”

“Keep me here?”

“I can’t let someone as battered as you out of my sight until I’m confident in your recovery,” Law says, gesturing at Sanji to turn over. He does, and Chopper shoves a rolled towel up against his back before he can put any weight on his sailfin.

“That would be unacceptably unprofessional!” Chopper chirps, peering up at Sanji with a fierce scowl.

“I promised to lead them to - well, I doubt they’ll want to let me stay,” Sanji explains, looking toward the entrance. The loudest splash yet echoes through, followed by Luffy’s laughter.

Beginning to wipe the accumulated dirt and blood off of Sanji’s long pectoral fins while Chopper fetches more supplies, Law only seems amused by his concerns. “They all know me better than to complain. Besides, you can’t even swim right now, can you, Sailfish-ya? Difficult to lead them anywhere like this.”

Sanji grimaces at that. He hasn’t had a chance to try, but the surgeon is probably right. While he doesn’t exactly like the idea of staying in Law’s cave for days, he can appreciate that the human is protecting him, in a way. Even if he doesn’t seem to think that Sanji is in any danger from Zoro and the rest of them.

When all of the obvious injuries are cleaned and tended, Law conducts a brief general examination, hands and eyes running along every inch of Sanji’s body. He frowns at the scattered bruises and prods the areas around the shark bite, checking for internal bleeding, and Sanji still only feels safe, even under such intense scrutiny.

Even when Law’s hands reach more private areas. Sanji can see the moment Law realizes where he’s touching, the slight frown deepening as his gaze meet’s Sanji’s for a split second. The doctor doesn’t back off, continues to probe along the different textures beneath Sanji’s scales until he’s satisfied with the examination, and Sanji can see the way Law catalogs every detail before drawing his conclusion.

“No signs of internal bruising,” Law carefully says. “Any other injuries?”

Sanji would have bet against Law knowing _what_ he was touching, exactly - Sanji doesn’t look anything like his seahorse mother, but there’s an expectant edge to the surgeon’s expression. “Think you got it all.”

“Any underlying conditions?” Law presses.

The distaste must be clear on his face. “Nothing,” Sanji bites out, resisting the urge to knock Law’s hands away from his waist. The surgeon isn’t touching him any more, but his hand on the edge of the table suddenly feels too close.

“It’s critical to know,” Law primly retorts, straightening up.

“Know what?” Chopper pipes up, coming back over to cling to Law’s leg.

Sanji is actually relieved to see Zoro stomp into the room, dripping wet and glaring. “Got your stupid tank figured out,” he grumbles.

“Excellent. If you would, Roronoa-ya?”

“Would _what_?”

“Assist Sailfish-ya into the other room, of course,” Law says impatiently. “And _gently_ , Roronoa-ya, I can nearly see your fingerprints bruised into his arm.”

“Gently,” Zoro mutters, stalking over to Sanji and sliding a hand beneath his tail. “Shoulda seen him thrashing around in the boat when we found him. Could hardly hold him down from making it worse, and you’re worried about a little extra bruising?”

Mutely, Sanji holds his own arms out and loops them around the swordsman’s neck when he leans closer. Zoro was concerned about him injuring himself further when they pulled him up? It doesn’t match Sanji’s memory of events, but the algae-head is careful now, as he wraps an arm around Sanji’s ribs and lifts him.

Being the dry one in this equation is weird. Sanji snickers, plucking at the soaked collar of the swordsman's shirt. “What happened, algae-head?”

“Damn bear got too excited, knocked Luffy in the water. Had to pull him out.” 

That explains all the screaming, and something Sanji had wondered about Luffy. The kid doesn’t move quite right, even for a human. “Devil fruit?”

“Just wait ‘til you see it,” Zoro sighs.

Back in the entry cave, Luffy is lying on top of the enormous bear, both just as soaked as Zoro and snoring hard. Law shakes his head, gaze resting fondly on the two of them as they skirt around into the next room. A few thick tubes trail out into the water, and Zoro has to step over them several times as they twist through the narrow corridor before the cave opens back up.

Instead of one large cave, this section is several smaller rooms, partially divided by shelving and boulders. The central space is dominated by a tank of seawater, the tubes connected to a cluster of devices attached to the side. 

“This is really complicated,” Usopp complains, crouched beside the mess of tubes and equipment Sanji can’t describe. 

“But he figured it out,” Nami adds, rolling her eyes. She looks fresh and relaxed, lounging in a chair a safe distance from anything wet.

Law only nods, walking up to the chest-high wall of the tank and sticking one hand in the water. “Good. Roronoa-ya?”

Zoro moves like he’s about to throw Sanji into the tank, but at a glare from Nami he slows down and lowers him into the water gently enough that it doesn’t splash everywhere. Gripping the edge as he unfurls his tail, Sanji is surprised to feel that the water is warm like a sunlit reef.

“Is the temperature comfortable, Sailfish-ya?” Law asks. “Any kind of strain will only hinder your recovery.”

“It’s nice,” Sanji confirms, and Usopp grins up at him.

“Great! This thing is pretty cool, it’ll regulate the temperature and make sure nothing gets in from the ocean, plus the water will stay fresh!”

Sure enough, Sanji can feel a mild current from the end of the tank with all the equipment. For a bare tub of water, it isn’t a bad place to recuperate for a while.

Everyone stares at him for a few moments, and Sanji is about ready to ask if they expect him to do a trick when Nami speaks. “So when can we leave?”

“Sailfish-ya shouldn’t swim for at least a few days,” Law says disapprovingly. “More time would be better, but you all can come back then and we’ll see how he’s doing.”

“I’m sure I’ll be fine, Nami-swan,” Sanji assures her. He doesn't want to test any of the humans’ patience, no matter what Law says. The sooner he can get them the treasure, the sooner this will all be over.

“Then we’ll take a day or two to get ready, and come back for you, Sanji-kun,” Nami decides. “How far away is this shipwreck?”

“In your boat…” Sanji isn’t really sure. He usually sleeps on the reef nearby when he goes out that way; it’s nearly a full day’s swim from his home, but their boat is slower than he can swim, and considering this island’s location… “Almost a day away?”

“We’ll plan a week’s worth of supplies…” Nami mutters, counting off a list to herself as she drags Usopp to his feet. “Come on, Zoro, help me wake up that idiot. Thanks, Law, we’ll see you later.”

Zoro lingers by the side of the tank, one hand on the edge as he glowers between Law and Nami. He follows her after a long moment, not sparing Sanji a backwards glance as he stalks out of the cave.

~o~O~o~

Sanji stays in the cave with Law and Chopper, enduring nearly hourly checkups while Nami and the others make their preparations. The room his tank is in turns out to be Chopper and Law’s main work space, with their separate offices in the partially divided areas off to each side. Further into the cave system, Law explains that they have more living quarters, and a tunnel that goes all the way to a small town at the top of the cliffs.

“That’s how I usually come and go,” Law adds, as he and Chopper arrange supplies for Sanji’s first bandage change the next morning. “The sea entrance isn’t exactly safe, especially for people like Chopper and I.”

People. The little monster too; Law treats Chopper like an esteemed colleague. He treats Sanji well, no differently than Sanji might imagine the surgeon treating any other patient. It’s kind of infuriating.

“You know the people in town?” Sanji idly asks. Not much to do in his tank beyond making conversation, and Law hasn’t been around to even do much of that.

Law nods. “Penguin, Shachi… I’ve known some of them for years.”

“Why live down here then?”

“It suits my purposes to be difficult to find,” Law responds with a thin smile. “Now let’s see to your tail, Sailfish-ya.”

Chopper brings him a float, so Sanji can drape his tail over it without straining himself, and another he can hold on to in order to keep his head above water more easily. It feels kind of strange, as Law steps up on a stool and pulls him closer to the edge of the tank, but floating in the water is much more comfortable than being laid out on the surgeon’s operating table.

“Do you two do this often?” Sanji asks. They seem so well-practiced at, well, everything.

“Medical treatment?” Law responds with a smirk. Sanji glares at him. “Take care of mers? No.”

“We treat all kinds of patients!” Chopper chimes in, leaning a short ladder up against the glass so that he can reach to check Sanji’s pulse and temperature while Law removes his bandages. “A good doctor is always prepared!”

They apply some more medication to his injuries, rebandage his tail, and largely leave Sanji to his own devices. Which means he spends a lot of time lying at the bottom of the tank and daydreaming, because it’s certainly not large enough to swim around in, and there’s nothing else to do. Law spends most of the day poring over massive books at one of the desks, and Chopper seems to be making more medicine, in between bouts of scurrying back and forth from one of the deeper caves.

Returning from one of these trips, Chopper brings Sanji a sandwich. Nothing special, much like the simple dinner last night and quick breakfast of fresh fruit this morning.

“Do you have a kitchen?” Sanji asks, propping himself over the edge of the tank to talk to the little reindeer doctor.

Chopper nods. “I’m not a very good cook, but Law forgets to eat a lot of the time. I try to take care of him, too.”

Sanji can’t imagine that Law makes it easy. “I could help, since you’re treating me for free and all. I like cooking.”

“You can’t leave the tank, drying out would be bad for your skin!” Chopper scolds.

“Well, you could bring me something to prep,” Sanji wheedles. Chopper’s stern expression wavers, and Sanji knows he’s won.

It passes the time. Waiting for Chopper to run back and forth checking on the ingredients available and bringing Sanji tasks he can do from the tank makes preparing a meal take easily twice as long, but there’s nothing else for him to do. Once dinner rolls around, Chopper is so proud of the quinoa salad they’ve tag-teamed that Sanji is a little embarrassed, and even Law’s eyes widen as he takes a bite.

Sanji doesn’t want to talk about it, so he accepts the praise and deflects the questions, and Law doesn’t push him. Chopper is too enthused about the meal to wonder why Sanji is so good at cooking human food, and his excitement continues throughout Sanji’s evening bandage change.

The next morning is much the same, but Law decides to leave the bandages off for a few hours, directing Sanji not to move around too much while he does some work at his desk. Enforcing this directive is Chopper, who makes frequent, unsubtle trips around the corner from his own project to make sure Sanji is still relaxing and not thrashing around in the tank, or whatever it is they think he’ll do to set back his healing. There’s still no space to do much more than float, even if he was so inclined.

“You’re a talented healer,” Sanji comments, looking at the mess of his tail. The edges of the wounds are closing remarkably quickly; Niji’s cuts already look weeks old.

Law glances up from his desk across the cave, and his expression twists in a darkly amused smile. “I’m no healer. My abilities are much better suited to cutting people up. The rest is all potions, and Chopper’s care.”

“Don’t say things like that, you bastard!” Chopper shrieks, looking at Law with an adoring grin before he goes back to mashing something up at his own little workbench.

“Chopper makes most of the surface applications, too,” Law continues. “Quite the gifted herbalist.”

“I don’t care if you think that!” Chopper protests, even though his tail is wagging so hard his entire body is wiggling. 

Meeting Sanji’s eyes, Law quirks an eyebrow, and his expression looks genuine and affectionate for a few moments. “The evidence speaks for itself.”

It’s true - after all the medical concoctions they’re put on and in him, Sanji’s tail barely hurts at all, and he’s eager to test how well he can move. But they don’t allow him to until the afternoon, as close as Sanji can guess in the artificial light of the cave. At any rate, he’s forbidden from doing anything strenuous until after he coaches Chopper through making a slightly more complicated batch of sandwiches, and some preparation for dinner.

“Tell us right away if anything hurts!” Chopper demands, scampering out of the room again. This time he runs out into the entry cave, and Sanji wonders if they have some kind of cart stored out there, or something. Law is a tall human, but Sanji doubts he has the muscle mass Zoro does. Carrying him out to the water isn’t an easy task.

“This may be disorienting,” Law tells him, stepping up to the tank with a smirk and an odd hand gesture. “Room.”

“Cold!” Sanji yelps, as his entire body hits water that is a much less pleasant temperature than the tank. Over his own splashing, he can hear Chopper chiding Law.

Getting his bearings, Sanji realizes that the surgeon has somehow transported him out of the tank and into the water at the entrance of the cave in an instant. Chopper is hovering at the edge, yelling over his shoulder at Law in between anxious glances at Sanji. Even Bepo has gotten interested in the action, getting up from his favorite corner and ambling over.

Sure, it’s cold, with that slightly dead feeling of water no sunlight ever touches, but it’s an overwhelming relief to be in the ocean again. No ropes, no bandages, nothing threatening him. It’s as good as warm reef water over his gills after a long dive.

“You could do that the whole time?” Sanji accuses, when Law meanders out of the inner cave. “Move me without touching me?”

“You shouldn’t have dropped him like that!” Chopper shrieks, running up to whack his little hooves against Law’s hip.

The surgeon only smirks again, patting the reindeer’s ears with one hand and Bepo’s with the other, and settling to the ground not far from the water’s edge. “Yes.”

“And you still made the shitty swordsman carry me around?”

“Zoro-ya is a hands-on type of man,” Law drawls. “Best to let him ascertain things in his own way.”

This is the first time Sanji has seen Bepo so close, and he only really understands how _huge_ the bear is when he noses into Sanji’s face, sniffing at his hair. Sanji flinches, a bit afraid to move as Law calls Bepo back in a chiding voice. Ducking his head, the bear sidles up to Law with the most comically apologetic body language Sanji has ever seen from an animal, but no matter how easy-going Bepo seems, Sanji isn’t eager to stay in his range for long.

Pushing away from the edge, Sanji does a slow underwater somersault, feeling the way his newly healing tail stretches. When he surfaces, Law is watching with a slightly more critical air, and Bepo is back by the wall, already barely awake. 

“What’s that supposed to mean, about the algae-head?”

“He may not act it, but Zoro-ya gets very protective,” Law shrugs. “Especially if Luffy-ya likes someone. He wasn’t comfortable leaving you with me, so it seemed prudent to let him see that I had done you no harm.”

“Prudent,” Sanji scoffs, instead of arguing over whether Zoro was _worried_ about him. That’s a ridiculous thought. “How do you know them, anyway?”

“Strawhat-ya and his friends are usually mixed up in some trouble,” Law dryly responds. “Rarely trouble of their own. I met them through one such misadventure, and once Luffy-ya gets his rubber claws into you, escape is futile. They come by whenever one of them needs medical attention.”

It’s hard to tell what Law thinks of Luffy and the others, but Sanji can’t imagine the surgeon tolerating them barging in on him all the time if he wasn’t fond of them in some way. Rather than press that line of questioning, Sanji leaves Law to watch as he swims circles around the cave entrance.

Looping around the small underground pool, Sanji feels optimistic about his recovery. He can’t get up to his full speed in such an enclosed space, but apart from feeling stiff and the occasional sharp pang when he bends too quickly, his tail doesn’t seem damaged. 

“You’re favoring that side,” Law comments as he returns, “but that’s to be expected. Don’t let it become a habit, or you could damage the muscles.”

“I wasn’t sure if I would be able to swim at all,” Sanji admits. Saying it out loud makes horror sweep through him, but relief is hot behind it. Splashing his caudal fin in the shallows - because he _can_ , because soon he’ll be able to go back to the ocean, back to racing through the open water at speeds no other creature can match - Sanji can’t help the emotional hitch in his voice. “I can hardly believe it’s this easy already.”

Law looks away, straightening the collar of his hoodie. “As I said, apart from the initial operation, you have Chopper to thank for that.”

Sanji snorts. This guy has an unexpected bashful side. “Dunno, I’m tempted to say you’re more of a mage healer than a doctor.” 

“Science, magic, devil fruit,” Law drawls, glancing back up. “At one point I may have insisted that medicine is best practiced with pure science, but that would be a difficult position for me to maintain now. Certainly Chopper’s work is more than mere herbs.”

“Not to mention yours,” Sanji mutters, but it’s clear the surgeon won’t take any more flattery than that. Hauling himself a little higher onto the rock, Sanji redirects his attention to his fins.

Raising his sailfin makes him wince, which has Law up and at his side almost instantly. “What hurts?”

“It just doesn’t feel right yet,” Sanji replies, rolling onto his stomach to give Law better access. The surgeon peers into his eyes like he’s looking for a lie, carefully feeling along the base of each spine. “Muscle thing from swimming with it torn, maybe.”

“You didn’t mention that,” Law frowns, lifting each spine in turn and prodding at the muscles along Sanji’s spine as they move.

“Uh, yeah, after Ni - after the thresher shark attacked, that’s what tore it initially, and then I had to swim with it that way until the idiots pulled me up.”

“They are idiots, aren’t they,” Law mutters. “Usopp’s ridiculous sticky net didn’t help matters, I’m sure.”

For a moment, Sanji thinks he’s gotten away with the almost-slip. There’s no real reason not to tell Law about Niji, but Sanji doesn’t want these people to know about his family. It will only complicate things, and imagining the look of pity he’s sure to receive makes shame curl hot and heavy in his gut.

“It’s an unusual wound, for an ordinary thresher shark,” Law comments, eyes sharp as he meets Sanji’s. “Difficult to see, what with the subsequent bite, but I’ve never heard of one being able to slice through flesh like that. So deeply, too.”

Sanji shrugs. He’s never seen more than shallow abrasions from that, either. “Unlucky day all around.”

Law obviously isn’t convinced - Sanji is beginning to think the human won’t believe anything he doesn’t see with his own eyes - but once again, the surgeon is content to let Sanji keep his secrets. A few more moments of silent examination, and Law warps Sanji back into the tank, calling for Chopper to make or bring all kinds of concoctions Sanji barely understands the names of.

He’s made to float at the top of the tank again while Law spreads a strange-smelling, hot cream onto his back, deft fingers unpausing as he talks shop with Chopper. Once the surgeon has finished Sanji is allowed to help Chopper finish dinner, but the cream has to stay out of the water, pulling tight as it dries and sinks into his skin and scales.

“I want to check your fins again in the morning,” Law says, dimming the lights in this cave as he and Chopper retire for the night. “Strawhat-ya will probably be back tomorrow, but they’re not known for getting going too early.”

“Okay,” Sanji manages, throat sticking as he realizes that this strange interlude of safety is almost over. The anxiety makes sleep hard to find, and Sanji spends a long time listening to the quiet noise of the tank pump, trying to pretend it’s the ocean’s waves.


	4. One Thing After Another

Whatever Chopper put in that cream, Sanji refuses to believe it’s only science, because when Law dumps him back into the water at the cave entrance the next morning, nothing hurts as he moves his sailfin. It still feels delicate, and Law spends a fair amount of time with Sanji draped over his knees at the edge of the water, replacing some of the splints and stitches, but Sanji thinks he’ll be able to swim without tearing it apart again.

His tail is almost as good, what looks like weeks of healing filling in the split edges and scabbing over the open areas. There’s still a massive dent in his side, and it’s red and raw in the center, puffy and tender around the edges of the wound, but Sanji isn’t afraid of losing strength in a current and being swept away to parts unknown, or any of the other horrific scenarios he’s been tormenting himself with.

Lying around while Law pokes at him is getting boring. Chopper is busy as ever, and Bepo is asleep up by the wall again; nothing to distract him from the surgeon’s hands prodding around.

“You don’t have to go with them, Sailfish-ya,” Law says, apropos of nothing. 

“I promised lovely Nami-san,” Sanji begins. He can’t figure out what Law means.

“You can stay here,” the surgeon explains, slowly, like he’s talking to a child. “I know there’s something you aren’t telling me about your injury. If one of them hurt you, I cannot in good conscience let you leave with them.”

“They didn’t - it’s nothing like that,” Sanji exclaims. He still doesn’t get it, and can’t turn to look at Law’s expression. The human has one hand against the small of Sanji’s back as he cleans out the wound with the other, swabbing yet another mysterious concoction into it.

“I can tell them you’re too injured to leave,” Law offers, sounding unconvinced. “There’s no reason you can’t draw them a map, if Miss Nami is insistent.”

Sanji doesn’t understand why Law would lie to them, lie for him. Luffy and the rest are his friends, and Sanji is just some random fish they dropped on Law’s doorstep. No one puts Sanji above anyone else, ever.

“As your doctor, I dislike sending you away without seeing your recovery all the way through,” Law continues, lifting a knee and urging Sanji to prop himself up on his arms, so the surgeon can put a new bandage around his tail. “Especially given that you are hiding things from me.”

A splash and muffled yelling echo up the tunnel to the ocean. Sanji twists to look, despite Law’s grip on the bandage only partially secured around his tail, and gets a glimpse of the surgeon’s frustrated frown as he does.

“TORAO!”

Unmistakeable, even though Sanji has only known Luffy for days. He’s torn between a resurgence of nerves about leaving with them, and relief that he doesn’t have to turn down Law’s offer in so many words. Too late now.

“Perfect timing, as usual,” Law mutters, tying off the bandages just as Luffy shoots out of the tunnel. Rolling off of Law, Sanji barely gets out of the way before Luffy bowls them both over.

As it is, Luffy ends up straddling the surgeon, jabbering about something he ate, and Sanji manages to get his tail under him before the rubber kid’s friends follow him inside. Fingering the new bandage, Sanji tries to school his face into something pleasant and welcoming, instead of showing his stress.

“- and _you_ don’t have a choice,” Nami concludes, looking over her shoulder to argue with Zoro as the two of them walk into the cave.

The swordsman growls at her, and a tinge of fear pings down Sanji’s spine. Even though Chopper has sung the man’s praises during several of his regular check-ups, prattling on about how Zoro is such a good guy, that they’re all such nice and helpful people, Sanji has spent too much time looking over his shoulder to let down his guard so easily. Growing up with his family situation will do that.

“Witch,” the swordsman mutters.

“You know it,” Nami retorts. “Hey, Law. Hey, Sanji-kun. Ready to go?”

“Certainly, mellorine!” Sanji confirms, giving her a bright smile as he watches Zoro sidle around her to check out the cave. The swordsman’s gaze hits on every entrance, sliding over Bepo asleep at the back of the cave and Law trying to get out from under Luffy, and finally settles on Sanji.

His expression is unreadable, and Sanji can’t help himself from glaring back. “What, algae-head?”

“Looking less like chum today, blondie,” Zoro sneers. “Half thought we’d come back to Trafalgar preparing your funeral.”

“Don’t mock me,” Law snaps, shoving Luffy off of himself with Nami’s help. “What kind of doctor would I be if I -”

“Torao’s a great doctor!”

“Luffy’s right, shut up,” Zoro drawls. “Just saying, this guy was a mess when we brought him in. Looks a lot better.”

It’s a compliment, Sanji realizes, seeing Law’s mollified expression and Zoro’s awkward glance to the side, breaking eye contact with any of them. Maybe even concern.

“Aw, were you worried about me, marimo-kun?” Sanji grins, fluttering his eyelashes. Zoro snarls at him, but Nami waves him off and runs a critical eye over Sanji’s bandages.

“Are you really recovered enough to leave?”

“I would strongly recommend leaving him here for at least a few more days -” Law begins.

“Practically good as new!” Sanji assures her. This time it’s Law glaring at him, and Sanji feels a bit guilty as he avoids the surgeon’s gaze. He doesn’t really want to go, but he doesn’t want to put Law between them, either. 

“I’ll help Chopper gather some treatments to take with you,” Law sighs.

“Me too!” Luffy chirps, and Nami chases after them, presumably to prevent Luffy from doing too much helping.

“Really?” Zoro quietly asks, and it takes Sanji a moment to track his line of sight and realize the swordsman is staring at his tail.

“How many times do I have to say it?” Sanji snaps.

Grumbling and shifting his feet, Zoro doesn’t do any of the things Sanji expects, like storm off to cuddle with Chopper, or insist that Sanji is lying, or ignore him and chase after Law to demand his professional opinion instead. No, he gets on one knee and reaches for Sanji’s tail, and Sanji is so astonished at the presumption that he just… lets Zoro do it.

The algae-head is much less delicate than Law, fumbling around the edges of the bandage with serious concentration. “Law will probably kill me if I take this off, huh,” he mutters, spreading his hands to either side of the wound.

“Or I will!” Sanji finally yelps. It doesn’t help that one of the idiot’s stupid wide, dry hands is right over _that spot_ at the top of his tail _,_ the warm pressure confusing with all the mixed-up emotions coursing through him. “Move your hands! It really is better, fuck!”

“Does it hurt?” Zoro asks. He doesn’t _move his fucking hands_. 

“No!” Batting the human’s touch away, Sanji tries to steady his breathing and stop the panicked fluttering of his gills. “You can’t just go around _groping_ me, come on -”

Zoro’s hands snap back to his sides at that, the swordsman leaning back on his heels with a shocked expression. “What the - I’m not - wait, is that where -”

“Stop thinking about it!” Sanji demands, smoothing one hand over his throat. Drawing air through his gills makes his voice strange and hoarse, not convincing enough. “You obviously never think, stop doing it now!”

“But you have fish parts, I don’t -”

“I said stop!”

“Stop what?” Chopper asks, trotting out into the cave. “Zoro, if you fight with Sanji, Law won’t let you take him with you.”

“Nothing,” Zoro mutters, red in the face as he turns to the reindeer. “Not fighting. ‘S fine.”

Appeased, Chopper’s attention lands on Sanji as he climbs into Zoro’s lap. “You can swim in that dressing, but it will have to be changed regularly. We’ve packed all the supplies, but someone will have to help you.”

Sanji nods, somewhat desperately not meeting the swordsman’s eye, and feels his own glaze over as Chopper launches into a seemingly endless spiel about how to properly care for the wound. There’s no way he’ll be able to remember all this.

“And come see us when you’re done,” Law adds, from right over Sanji’s shoulder. He startles; the others barely made a sound as they came back.

“Right,” Sanji promises.

Luffy’s mouth is full - that must be why he was so quiet, as Nami drags him toward the tunnel. “Thank Law,” she says. “Usopp is waiting with the boat, so we’d better get going before he convinces himself that some imaginary sea monster is stalking him. C’mon, Zoro, grab Sanji-kun and get over here.”

Sanji is not eager to let the algae-head carry him after their little incident, but Law’s smile is vaguely malicious as he takes Chopper off Zoro’s hands. No help coming from him, then.

“Be gentle!” Chopper orders, as the swordsman reaches for Sanji. “Don’t agitate the wound! And his fins, I _know_ you weren’t careful, they can tear really easily -”

“I’ve got him,” Zoro growls, easing Sanji up with an arm much farther down his tail than other occasions. The other, wrapped around below his shoulder blades, is starting to feel secure and supportive, rather than threatening.

“Just be careful!” Chopper insists, nearly falling out of Law’s hold to wave his hoofs at Zoro. “And come back soon!”

“Soon as we can,” Zoro agrees, hefting Sanji into a more comfortable position. Head resting on the swordsman’s shoulder, Sanji turns his face into Zoro’s collarbone to avoid Law’s smirk.

“Hurry up!” Nami yells, voice echoing down the tunnel. With another growl, Zoro spins on his heel to follow her.

“Take care of yourself, Sailfish-ya,” Law calls after them. Pulling himself up enough to peer over Zoro’s shoulder, Sanji finds himself hoping this won’t be the last time he sees the odd pair.

“Thank you!” he yells, right as they turn a corner into darkness.

Zoro winces. “Don’t scream right in my ear.”

“I’m not screaming, algae for brains, but I couldn’t leave without saying something, don’t you have any manners?”

“Next time say it before your fish breath is all up in my face!”

“I don’t have fish breath, idiot,” Sanji pauses, remembering his goal to improve Zoro’s opinion of him. Probably still a good idea, one he should work on, but… “I smell great. You have no taste.”

“You _literally_ smell like fish and ocean brine, in what world is that a good smell?”

“Of course your primitive human nose can’t capture the nuance,” Sanji sniffs as Zoro carries him into the light at the end of the tunnel. “It must be hard to be so ignorant.”

“There you are!” Nami exclaims impatiently.

“Sorry, Sanji, but Zoro’s right this time,” Usopp pipes up. 

“Humans,” Sanji scoffs, apprehensive now that they’re out in the open. It’s a calm morning, the little boat rocking gently at its mooring, sunlight already beaming down. He isn’t sure how guiding them to the shipwreck is supposed to work, but he hopes he won’t have to sit out in the sun to do it.

He’s more prepared for Zoro’s careless leap into the boat this time, only catching his breath a little at the lurch. The swordsman still scoffs at him, but Zoro looks like he’s hiding a grin as the boat rocks.

“Show him, show him!” Luffy demands, tugging at Zoro’s sleeve. “Look, Sanji, we built you a tank!”

“ _I_ built it,” Usopp mutters, before putting on a winning smile and waving at the prow of the boat. “You get dry pretty easily, right, Sanji? There’s not a lot of space, and we can’t run the pump while the boat is moving, but hey, it’s water, right?”

Sanji is so shocked he can barely speak. Modifying their boat so he’ll be more comfortable? Why would they do something like that?

“You better not complain about it,” Zoro mutters, clambering over the seats to get to the prow. “Usopp worked really hard.”

“That’s not - I would never!” Sanji snaps. “I’m surprised, bastard. I didn’t think you all would care.”

Zoro scowls at him like that’s no better, and Usopp looks startled for a moment before scrambling over to talk more about his modifications. It’s a small tank, like he said, but plenty big enough for Sanji to keep his tail submerged, and they’ve even erected a little canopy above it.

“Zoro said we should put an umbrella up,” Usopp snickers, elbowing the swordsman after he unceremoniously drops Sanji in the water. “As if it wouldn’t blow away in seconds.”

“But you added the tarp thing,” Zoro grumbles, shoving Usopp into the pole supporting said tarp before fleeing the scene. 

There’s even a board fastened to the front, so Sanji can lean on it and look out at the ocean. Watching Zoro’s hunched shoulders, Sanji leans over the back edge to talk to Usopp instead.

“The algae-head suggested the canopy?” The idea is much too thoughtful to fit Sanji’s picture of the human, but it suits the way Chopper and Law talked about him.

Usopp sits on the seat that now makes half the back wall of the tank, and shrugs. “Once I could translate it into something that would work, yeah. He said you were real messed up, when we left that first day. I mean, your tail, obviously, but Zoro said your skin - scales - whatever, that we’d kept you out in the sun too long.”

“Not your fault,” Sanji mutters.

“Should’ve been obvious, though,” Usopp says, with an apologetic smile. “Uh. Thanks for still agreeing to help us with this.”

Sanji rather thinks Usopp has the order of thanks wrong, but he isn’t stupid enough to say so. “How is this gonna work, anyway?”

“I have a map,” Nami announces, whacking Usopp with a roll of heavy parchment as she comes over. “Get us off the coast, Nose-kun, while I figure out our course.”

She unfurls the map over the seat, and Sanji is relieved to see that it’s at least a nautical chart, and not a more simple style of human map. Most of them don’t even show major currents; Sanji has no idea how the humans can use them for anything, but this one has the main depths, currents, and even tidal discrepancies marked for a wide swathe of the nearby islands.

“It’s out here,” Sanji says, pointing to the largest empty area on the map. No wonder human salvagers never head out that way, if this is what their maps look like - the entire section of ocean is blank, no land masses at all, and several strong currents curving around the area. Much easier to hop from island to island, and no reason to try navigating what must look like a dangerous and fruitless stretch of sea.

Nami trails her fingers along the marked currents, mumbling under her breath as she traces a path from the island they’re leaving. “Okay. Anything special we should know?”

Shaking his head, Sanji mimics part of her path. “If you catch this current part of the way, it won’t even matter what the wind is doing. This time of year, it’s especially strong, but once we’re across it, there’s nothing tricky out there.”

“Perfect.” Nami rolls the map back up, yelling instructions to the others, and they’re off. For a while, everyone is busy doing all the incomprehensible things humans need to do to keep boats moving, and Sanji is left to watch the waves flash past under the prow.

That afternoon, Luffy comes to talk to him. Sanji can’t help shying away - he hasn’t been this close to the kid, not since watching him eat that piece of Sanji’s tail, and Luffy’s wide, careless grin is still the same. Easier to understand, after seeing Law’s fond resignation, but it takes Sanji a while to beat the unease.

Luffy bounces on his heels, asking so many random questions in such rapid succession that Sanji can't keep up. He can only conclude that Luffy is exactly as crazy as he ever suspected, but the kid sure is fun to talk with. Unfortunately, once Sanji lets slip that he likes cooking, that’s all Luffy can focus on, drooling into the tank as he puts his face barely a breath from Sanji’s.

“Wanna be a pirate? We’re gonna need a cook, it’ll be fun! You’d be a great pirate, I’m sure of it. That’s it, I’ve decided, Sanji, you’re gonna be my cook!”

“Leave him alone and come trim the sail!” Nami shouts.

“But Sanji is so cool, he’s going to cook for us, it’s really important -”

“Getting the _treasure_ is important, or we won’t have a ship, and then nobody will get to be pirates!” Nami yells. “Get over here!”

Sanji watches them somewhat warily after that, unsure what to say if Luffy insists. Apparently the kid can’t see all of the reasons that Sanji becoming his cook just won’t work out.

They shoot out of the current as the sun is beginning to set, and Nami brings him a snack. Sanji can’t thank her profusely enough, but after a few minutes of trying, she waves him off.

“If this treasure is really there, we’ll call it even,” she promises.

“We’ve made better time than I expected,” Sanji says. “I didn’t think human boats moved this fast.”

Nami smirks, tossing her hair over her shoulder. “You won’t find a better navigator than me. If there’s a shortcut, I’ll find it.”

Sanji remembers Zoro calling her a witch, and wonders if reading a map is the extent of her skill. “They’re lucky to have you, my dear!”

“Don’t I know it,” she sighs. “Luffy’s like that, though. The rest of us work harder so he can stay so free.”

These people say the strangest things. Once again Sanji doesn’t know how to respond, and Nami quirks a darker smile at him. “Hope nobody’s waiting for you at home,” she adds, going back to yell at the boys again.

Sinking into the tank, Sanji can’t stop those words from simultaneously sinking into his head. The reality of them sits like a stone in his stomach - nobody is waiting for him. Vaguely, he wonders what his brothers told Judge, after they left him to the sharks, but it doesn’t really matter. Sanji will go slinking back eventually, if only because it’s too hard for a lone mer to survive in the open ocean. He’s tried. If Sanji was human, he might even take this crazy kid up on his job offer.

A heavy clunk on the seat, and something flicks the end of his tail, where submerging his torso has forced it to curve above the water level. Taking a swing, Sanji bats the offending something away, and comes up glaring.

Of course it’s the swordsman, shaking the sting out of his hand with a glower to match Sanji’s. “We almost there?”

“Ask your navigator,” Sanji snaps.

“The witch says we’ll get there when we get there,” Zoro grumbles, settling more firmly on the seat.

Sanji stares out at the empty waves around them, and tries to guess where they are. It’s so different from up here, without the familiar feeling of the currents around him. “It can’t be far now.”

“Real specific.” Propping an elbow on the edge of the tank, Zoro watches him for a few seconds before closing his eye, apparently content to invade Sanji’s space without offering any further conversation. Not that Sanji wants to chat with the muscle-brained idiot, but it’s been a boring day in the long stretches between these strange conversations. 

“All the grace of an ocean sunfish,” Sanji says, reaching out to poke the man’s bicep. Zoro doesn’t twitch. “Hey, algae-head, you ever seen an ocean sunfish? One of the big ones. They float along in the current, wherever fate takes them. Almost as stupid as jellyfish, but way less beautiful. Kind of like you, sleeping your way through life.”

“Do you ever shut up?” The swordsman asks, cracking his eye open to make a grab for Sanji’s head.

He only laughs when Zoro pushes him under. It’s a move that must work on Usopp or Luffy, but it’s just dumb to use on Sanji. Talking is harder, sure, but Zoro can’t keep him under forever.

When the idiot lets him up, Sanji wrings his hair out over Zoro’s arm. “If you’re going to sit here, you can at least keep me entertained.”

“You should have taken the opportunity to nap,” Zoro says mulishly. “Nothing to do but bother the rest of us, damn.”

“I got enough sleep at Law’s,” Sanji dismisses. 

“He’s a standoffish guy, but it looked like you got along,” Zoro comments. Sanji can’t quite read his expression.

“Yeah, unlike you, he’s civilized.” Sanji rolls his eyes, enjoying the swordsman’s frown.

“Maybe if you weren’t such a pain -!”

“What, do you want me to be nice to you? Didn’t think you were so sensitive, algae-head.”

Zoro turns his head away, and Sanji leans up on the edge next to him. “Back off, curlicue.”

“If you weren’t so grouchy, I’d be nicer,” Sanji coaxes. He’s not sure if that's possible, or true, but Zoro’s ears are turning red in embarrassment, so he _has_ to keep teasing. Leaning farther out of the tank, Sanji pokes at the human’s bicep again. This guy really is solid muscle. It’s kind of impressive, in an unrefined way.

“I don’t want you to be nice, I want you to get out of our lives,” Zoro retorts, side-eyeing him without giving ground despite the flush spreading down his neck. “Stop making that face.”

Sanji gives an exaggerated pout, resting his chin on his hands so close to the swordsman that he can feel the sun-infused heat radiating off his skin. “So rude.”

Seducing this idiot probably isn’t necessary any more, but going through the motions of flirting with him is kind of fun. And if it works, well… Sanji doesn’t trust these people yet, so it would still make him feel more secure to have that kind of sway over the swordsman.

Zoro shifts, beginning to push him away again. “What did I say about your fish breath -”

“Hey, is that land? It’s definitely land, I mean, LAND HO!” Usopp excitedly shouts.

Out in this vast stretch of open ocean, there’s a reef. It’s strange, almost like a landmass has gone missing - there’s no volcanic activity nearby, no other irregularities in the seafloor to explain the shallow area. Just a sloping rise maybe a league in diameter that ends an abrupt dozen feet below the surface, with one jagged bit of island poking above the waves.

“How do you know about this, anyway?” Zoro asks, eyeing him suspiciously as the boat slows, navigating the shallows up to the island.

“Found it,” Sanji snaps. Why shouldn’t he know a few interesting places in the ocean? It’s where he _lives_.

“All the way out here?” the marimo demands. “How?”

“I swam,” Sanji says, rolling his eyes. “Not many mers better suited to the open ocean than I am, not that an idiot like you would be able to figure it out.”

“As if I would spend my time learning that much about different kinds of fish,” Zoro jeers.

“Yeah, maybe if you had, you’d be better at catching the right ones,” Sanji mutters. They’re still a ways out from the tiny island, but now the seafloor is visible beneath the boat. Leaning over the side to watch the reef slide by below them, Sanji all but forgets about the algae-head.

It’s a beautiful reef. Sanji stares into the water as if he’ll be able to see through the distortions of the waves by sheer will, trying to make out the familiar seascape of bright corals in the abstract swirls of color. Silver flashes of barracuda cut across nearer to the surface, everything else too blurred to make out at this depth.

In the back of the boat, Luffy is chattering about getting to the island, while Nami insists that they aren’t close enough yet. Sanji can’t understand why she has to say it - obviously they’re too close to jump, and it would be pretty far for a human to swim even if Luffy _could_ \- until something makes a loud _twanging_ noise and a blur of red shoots over his head.

Gaping, Sanji can just make out Luffy’s odd laugh fading into the distance. “What.”

A puff of sand rises from the tiny island. “Rubber,” Zoro sighs. “Gum-Gum fruit, is the one he got. Sounds pretty damn useless until you see him do something like that.”

The other two are also shaking their heads with deep resignation when Sanji turns to look. “One of these days he’s going to overshoot,” Nami mutters, “and then what? We’re too far away to pull him out.” 

It never stops with these people. Ignoring the cavalier speculation about Luffy’s inevitable death by drowning, Sanji goes back to watching the ocean floor as they sail nearer.

“It’s too late to do anything tonight,” Nami decrees as they land the boat. “I want plenty of time to get the treasure, so we’ll start bright and early.”

Sanji eyes the shore and the humans with some trepidation. Are they going to tie him up again? He’s not planning on trying to escape from them here; it’s too far from anything, with his tail still injured. The water in his tank is getting unpleasantly warm and stale, but he would rather stay in here than get thrown out onto the sand -

“Good thing we brought that camp stove,” Usopp comments, peering at the island. There’s not much to it, just a couple of palm trees and white sand over the fragment of bedrock. “You hungry, Sanji?”

“Yeah,” Sanji cautiously answers.

“Then see if you can find some scallops or something,” Nami instructs, tossing him a net bag and pointing back out at the reef. “Make the stew we packed more interesting. Give Sanji-kun a hand out, Zoro.”

“You just want to save money,” Zoro grumbles, but he holds out his arms to Sanji anyway, dumping him overboard off the back of the boat with no further ceremony.

Sanji floats there for a few moments, but the humans have already stopped paying attention to him. Yelling orders to Usopp and Luffy, Nami doesn’t so much as look back.

“Tail okay?” Zoro gruffly asks, turned away from Sanji to watch the commotion on the beach. He crosses his arms over his chest and throws a quick glance over his shoulder, all scowls. “Scream if you can’t swim, or something.”

“It’s fine, algae-head,” Sanji snaps. “Go help the lovely lady.”

They glare at each other for a long moment, before Sanji gets the last word by flipping underwater to send a huge splash over the side of the boat. Zoro’s outraged spluttering is barely audible as he zips away beneath the waves.

The real ocean, alive with currents and the warmth of the sun and the deep chill of water rising from the depths, full of fish and crabs scuttling through the rocks and soft corals clinging to the shallow outcroppings of rock. Feeling weightless with relief, Sanji takes a quick lap around the island, confirming that everything looks the same as the last time he came here, before making his way out onto the reef proper.

Collecting some shellfish he knows humans find palatable, Sanji takes his time to really stretch and adjust to the limits of his current swimming ability. Nothing bothers him, the energetic expanse of the reef home to only small predators and hosts of brilliantly colored fish. He disturbs a toothy moray eel from its hiding place amongst the coral, lets a cloud of cleaner fish nibble at a few patches of peeling scales, and simply enjoys drifting through the deeper channels between sections of reef.

Before heading back to shore, Sanji swims out over the dropoff closest to the island. Closest, and sharpest too, the seafloor falling away much more steeply than anywhere else around the edge of the reef. Here, wedged down nearly invisible in the depths, the bones of a ship lie trapped in a jagged shelf of stone, jutting out from the drop with nothing but dark ocean and cold currents below it.

This, too, looks unchanged. It’s eerie in the failing light as the sun sets, so Sanji doesn’t linger, content that at least time and decay haven’t finished pulling the ship down into oblivion.

The humans have settled down by the time he returns, with several tents set up around a little portable stove. They’ve made their camp right by the shore, close enough that Sanji can slide halfway onto the beach and speak with them where they’re sitting around the stove without drying himself out.

“Did you find meat?” Luffy demands, bouncing over.

Sanji starts to hand over the bag, but Nami drags Luffy back by the collar, and Usopp has to scramble over to take it. 

“There’s meat in the stew,” Nami scolds.

Scooting closer and sitting up on his tail, Sanji peers at the stew they have heating over the stove. It doesn’t smell like something that would taste very good with shellfish, but there’s a haphazard pile of basic cooking implements beside one of the tents. 

“Do you have any seasonings?” he asks. “I can cook those separately.”

Judging by how understocked their fishing hut was, it’s a long shot, but if they have _something_ Sanji should be able to make a decent dish. Along with the shellfish, he picked up a few kinds of edible seaweed that he intended to eat raw himself, but they would be good sautéed, too.

“Oh! I might!” Usopp exclaims, rummaging around in his bag and offering Sanji a double handful of mismatched bottles.

“Why do you have so many kinds of hot sauce,” Sanji mutters. Confusing as the collection is, there’s also garlic powder and salt, so he’ll take what he can get and not ask too many questions.

Usopp chatters on about itching bombs and some kind of horrible slingshot ammunition involving the hot sauce, but Sanji ignores the shameful misuse of ingredients and corrals him into helping to prepare his catch. 

“You’re so fast at that, you don’t need my help,” Usopp complains, watching Sanji remove the invertebrates from their shells. The pile of shells at his own feet put the lie to his words - Usopp talks more than anyone Sanji has ever met, but he has clever hands. “What are we making?”

“Why are you putting vegetables in it,” Luffy whines, from the other side of the stove, where Nami has tied his arms in knots and is sitting on him to prevent the kid from getting into the stew.

“It’s just a seafood sauté, nothing fancy,” Sanji says, before shooting a glare at Luffy. “And without the seaweed it would just be sautéed shellfish, and I’m a better chef than that, so you’ll eat what I give you!”

Contrary to his intention, Luffy only snickers, and Usopp shrinks back with a squeaky comment about being allergic to asking questions. 

“Wasted on these guys,” Nami sighs.

Throughout all the commotion, Zoro has been asleep by the tents, but he cracks his eye open to scoff at that. “Probably some weird fish recipe you won’t even like.”

Sanji flicks an empty shell at his head, but the swordsman knocks it out of the air. “See if you get any of it then, asshole.”

“I want some,” Luffy begs, squirming around under Nami as Sanji drags himself closer to the rickety stove.

There’s no reason to dignify something that obvious with an answer. Instead, Sanji asks Usopp to show him what equipment they have, and gets all his ingredients together in a pan. Actions speak louder than words, and the stupid algae-head will be speechless once he gets a taste of Sanji’s cooking.

Nami passes out a stack of dented tin plates, and by the time Luffy has untangled his arms from her knots, everyone else already has a serving of stew and Sanji’s sauté. Good thing, too, because Luffy takes possession of the entire pot and inhales his plateful of Sanji’s cooking between one breath and the next.

“Yum! Sanji, hey, is there more?”

“Leave the fish alone,” Zoro grumbles, batting the kid’s hands away from his own plate. “You can see there’s not.”

They’re all too busy fending off Luffy to say much for the next few minutes, but Sanji doesn’t miss the surprised-pleased-grateful expressions that pass across Usopp and Nami’s faces in quick succession as they eat his food. Even Zoro’s eyebrows go up, and he flicks his gaze toward Sanji for a startled moment after taking that first bite. Not much response, but it’s genuine, and Sanji isn’t sure what he would do with more praise than that, anyway.

The stew they brought is… not terrible. Dried beef with an unpleasant rehydrated texture, too much salt; Zeff would certainly never serve it, and his brothers would surely never deign to take more than one bite, but Sanji eats his entire serving.

When he finishes, Zoro is staring at him. Usopp takes his plate, gathering it with the rest of the dishes and prying the stew pot out of Luffy’s hands. “You really can cook,” the swordsman says, as Usopp goes to scrub the dishes out in the shallows.

“Why would I lie about that?” Sanji snaps.

“Isn’t that what mermaids do? Sirens luring sailors to their deaths, promising the impossible, all that?”

“I mean, sure,” Sanji frowns. “But cooking?”

“The only luxury he cares about.” Zoro jerks a thumb at Luffy, still trying to lick the last remnants of stew off the pot. 

“As if a siren would bother trying to seduce Luffy,” Nami snorts, getting to her feet. “Thanks for the help, Sanji-kun. Zoro, take first watch.”

Zoro levels her with a baleful glare as she retires to one of the tents, but keeps his mouth shut until the flap swings shut behind her. “Witch.”

“Is she really?” Sanji wonders. “She seems confident enough.”

“Ask her yourself,” Zoro scoffs. “I still don’t trust you, even if your food has the rest of them charmed.”

“I’m not ensorcelling or seducing anyone, least of all that crazy kid,” Sanji protests. Or rather, he’s been trying to charm Zoro, and gotten entirely ignored.

“Good,” the swordsman snaps.

Sanji steals a glance at the kids - now roughhousing in the shallows, cleanup forgotten - and rolls onto his side. Sitting up on his tail for so long is uncomfortable. “What’s the problem, algae brains, jealous?”

“Of _what_?”

“I dunno, whatever you’re all wound up about?” Shrugging, Sanji stretches a little and runs a hand over his hip and bandages. Feels normal enough. 

“You,” Zoro glowers.

“Right.”

Neither of them really looks at the other, listening to Luffy and Usopp as the last hints of sunlight fade out of the sky. The stars are more than bright enough to see by, but Sanji is content to stare up at them instead of trying to figure out Zoro’s expression.

The swordsman isn’t as aggressive as he acts, that much is true. He’s protective of his friends, like Law said, and it’s easy to see why, with Luffy as trusting and carefree as he is. They’re all idiots.

Eventually, the splashing quiets, and the two kids trudge back to the other tent. Zoro sighs, and glances down to meet Sanji’s eyes. In the deep shadows, Sanji isn’t quite sure, but he thinks the swordsman quirks a smile as he speaks.

“You’ll never be free of us now, you know that, right? Luffy doesn’t have any friends that can cook, he’s never gonna let you swim off.” 

Oddly, Sanji doesn’t feel threatened by the idea. Lying here under the stars, he’s almost flattered. No one ever _wants_ to have him around that way. “I wouldn’t let you catch me twice.”

Zoro scoffs, reaching over to poke at Sanji’s bandages. “Say that again when you’re better. I saw you earlier; didn’t look so fast to me. Need help changing this?”

“I’ll show you fast, just wait for tomorrow, algae brains,” Sanji mutters, rolling closer to let the swordsman unbind him. Once they’re off Zoro has to get up to fetch the fresh bandages, and Sanji watches him move without any of the usual trepidation. The idea of having the human so close isn’t spiking him with fear any more.

Maybe he’ll have a chance to see them again, once this is all over. They won’t be like Zeff, sailing a track around the same stretch of sea in his floating restaurant, but Sanji would like to see these idiots off, once they get their ship and sail away into the greater ocean. Like Law and Chopper kept saying, the lot of them really aren’t so bad.

Zoro is still rough as he wraps Sanji back up, oblivious of his own strength, but Sanji can’t interpret his insensitivity as malicious. No more than Zeff’s gruff teaching methods, or Reiju’s cold practicality when she deflects his brothers’ attention.

Hands lingering over the knots, Zoro peers into Sanji’s face again, and Sanji thinks this might be how he really ends up in trouble. A thousand and one fables tell him as much, that a mer who gets too close to humans will always die messily because of it. He’s already tempting fate, with his relationship to the old geezer.

“Thanks, nurse,” Sanji quips, and the swordsman glares, whipping his hands and gaze away. Pushing himself up on his arms, Sanji slides back toward the water. “I’m gonna get some sleep.”

“Rest up,” the human snaps, “‘Cause the witch is gonna run you ragged tomorrow, curly.”

As Zoro stomps off - all of a half-dozen strides to the opposite side of the tiny island - Sanji circles the shallows until he finds a comfortable place to sleep. It’s a little exposed, but after the silty mangrove roots and stuffy tanks, he’s not going to complain about the gentle currents flowing along his tail. A cluster of fan corals wave above him, scattering the starlight, the silent silhouettes of a few small nocturnal sharks glide past, and Sanji feels almost as relaxed as he can ever remember being as he falls asleep. 


	5. Treasure Hunting

The next morning, Sanji awakens to splashing and yelling, as Luffy tries to swim out to where he’s sleeping to wake him up. He can’t, of course, so the splashing is half his efforts and half Usopp desperately trying to pull the rubber boy out of the shallows, and the yelling is Nami berating them. When he pops his head above the water, Sanji can see Zoro yawning on the edge of the beach.

“Treasure hunting!” Luffy yells, dangling from Usopp’s arms as the ocean drains the strength from his limbs. “Sanji, show us where the treasure is!”

He keeps trying to get out of Usopp’s grasp until Nami sighs, retrieves a piece of jerky from their supplies, and waves it out in front of her like she’s tempting a pet. That gets Luffy safely back to solid ground, and Usopp trudges behind him, soaked through.

It’s a lot of excitement so early in the morning. The sky is still pink around the edges, the air still calm with the quiet of night. Of course, the reef is bustling as ever as he swims back through the shallow outskirts to shore. An ecosystem like this never fully sleeps.

Picking up a few shellfish on his way in, Sanji wonders if he should offer to catch some fish too. He’ll be able to do it faster than the humans with all their fiddly equipment, and food is clearly a good way to ingratiate himself to all of them.

“Luffy is staying on shore,” Nami says, handing him some kind of cereal bar when Sanji reaches the beach. “Usopp and I will handle the boat, so you and Zoro can get the treasure. Eat up, Sanji-kun.”

“O-oh, thank you, Nami-swan!”

“But I want to come,” Luffy whines.

“I can’t concentrate on you and the treasure at the same time!” Nami snaps.

“I’ll stay with him,” Zoro mutters.

“What did I _just_ say about your job?!”

Nibbling on his breakfast, Sanji watches them bicker and lounges on the sand, entranced by the casual familiarity in the scene. It feels almost natural to chime in with support for Nami-san, in her infinite wisdom, and flick salt water at Zoro when the swordsman scowls at them. Dangerous. He shouldn’t be so at ease with these humans.

Nami wins out in the end, of course, and Luffy settles despondently on the shore as the others get into the boat. They don’t ask Sanji to get into his tank, instead letting him lead them around the coast through the water. It’s a leisurely pace for Sanji, who loops and twists under the boat as the humans maneuver it over the waves.

When he comes up Zoro is watching him, leaning over the edge of the boat to stare into the water. It’s startling, and Sanji misses a stroke, spinning a little as his sailfin wobbles.

“What?!” he demands, rolling onto his back for a few strokes to make giving the swordsman a rude gesture easier.

“Nothing,” Zoro retorts, hefting himself up and turning away. “You look… like you’re enjoying yourself, is all. Swooping around like a dolphin-seal or something.”

“I’m much more graceful than a dolphin-seal,” Sanji protests, once he gets over the initial bout of speechlessness.

“Didn’t say you weren’t, just that you’re playing around like one,” Zoro says, rolling his eye.

Sanji narrows his eyes. That almost sounded like the human was calling him graceful. “Excuse me for enjoying myself.”

“Must mean you’re feeling better, so ‘s not a bad thing,” Zoro offhandedly says, casting Sanji another unreadable glance before vanishing to the other side of the boat, fixing some of the lines under Nami’s detailed instruction.

Diving under the boat’s shadow, Sanji tries to compartmentalize the fizzy muddle of emotions that exchange evoked. He can’t quite sort it out, and now they’re passing over the dropoff - there’s no time to wonder what the swordsman meant. Below him, the shallow expanse of white sand falls away, leaving only deep blue oblivion with the humans’ tiny boat bobbing above it.

Sanji leads them along the edge until Nami can drop the anchor in the shallows right above the sunken ship. He goes down to check it, making sure the anchor won’t pull away from the top of the underwater cliff, and returns to the boat.

“You should be able to see it now,” he informs the humans, pulling himself up to cling to the side of their boat. Shaking his wet hair out of his eyes, Sanji nods over his shoulder, and the whole boat rocks as they all rush to look.

“Wow!” Usopp gasps, leaning so far over that Zoro puts a hand on the collar of his shirt. “I’ve never seen - I mean, the Great Salvager Usopp has explored dozens, no, hundreds of shipwrecks, great treasure ships forgotten by history, and some so far into the depths that no sunlight can reach -”

“How far down is that?” Nami interrupts. 

“It’s pretty deep,” Sanji hedges. He can go into much deeper water before risking pressure sickness, but he has no idea what the safe limits for humans are.

Nami peers over the side. The water is clear and calm this early in the morning, and Sanji knows how that can play with your perception, make things look so much closer than they really are. Shaking her head, Nami starts pulling a length of tubing out of the seat compartment beside her. “We’ve got this. Get over here, Zoro.”

“You’re the worst,” the swordsman grumbles, but he’s already laying his swords aside and taking off his outer coat. “Why don’t you go down, if you’re so excited about the treasure?”

“You can’t ask her to -” Sanji indignantly begins.

“She’s asking _me_ to,” Zoro points out.

“I’m not asking,” Nami deadpans.

Behind them, Usopp groans. “At least you’re not asking _me_ , I have a horrible case of can’t-explore-shipwrecks-that-are-barely-clinging-to-cliffs disease, it looks like that thing might fall off any second.”

“What happened to _hundreds and thousands of shipwrecks_ -”

Shaking off his annoyance, Sanji tries again. “How well can you swim, algae brains? Like I said, it’s a deep dive.”

“Doesn’t matter,” Nami smugly says, holding up an odd helmet attached to the length of tubing. “All he needs to do is sink.”

“I swim fine,” Zoro mutters. He scowls as she pushes the helmet into his hands, but doesn’t keep protesting.

“Is that safe?” Sanji asks dubiously. It has a thin-looking glass window on the front, and the tubing looks awfully delicate, too.

“The Great Inventor Usopp’s Treasure Retrieval and Deep Sea Investigation Headset is perfectly -”

“That’s model three,” Nami interrupts, waving at Zoro to get on with it. “And Franky’s helped a lot, getting better materials. They’ve worked out the kinks by now.”

“The air line only snapped _one time_ ,” Usopp says under his breath.

Zoro’s expression goes a bit pale, but he puts on the helmet, immediately tangling himself up in the tubing. “Don’t remind me. Let’s get this over with.”

Sanji resigns himself to keeping a close eye on the swordsman. If the human drowns because of that ridiculous device, the others will certainly say it’s his fault.

Even if he can keep the helpless, air-dependent human alive and retrieve enough treasure to grant all their wildest dreams, there’s no real safety in it. Even now, floating above the sunken ship, Sanji is convinced that Zoro will kill him on the spot if he makes a wrong move, anything that puts the others in danger. What that might be, Sanji isn’t sure, but he can tell the human swordsman is watching for it. No amount of quiet bandaging and subtle jokes will change that.

“Don’t fuck this up for me,” Nami warns, hands on her hips as she cranes to stare Zoro in the eye. She hands him a net and the end of a rope, tied off to a small winch by the mast, and gestures into the water.

“We’ll be back before you know it, Nami-swan!” 

“Bring back lots of treasure, Sanji-kun!” 

They dive. Or, rather, Zoro jumps overboard with his legs straight and his jaw clenched tight behind the helmet’s window, and Sanji swoops after him as the swordsman sinks toward the shipwreck, trailing tiny bubbles alongside his air line.

The wreck is no less unsettling in the daytime, even wreathed in schools of silver-flashing fish and shafts of sunlight. The design is too strange, with its broad, unwieldy hull and barrel-like curved top, more of an ark than a modern sailing ship. Oar ports, long empty, line the sides, and the shattered remains of some kind of wheel still stick up from the back. When it sank, the ship went down prow-first, despite the evidence of critical damage in the form of a large hole just below the waterline under the last of the oar ports.

Of course, by now, much of the ship is skeletal, the outer boards broken and disintegrated. Sanji can see through it all the way to the glint of sunlight off the bizarre figurehead, where most of the upper cabin areas have been torn open by the ocean currents.

It’s the lower hull that matters, inner rooms still practically intact as time and salt eat away the outer layers first. Beckoning to Zoro, Sanji slips through the massive hole and tries to remember the most direct route into the treasure hold.

Several times, he has to swim back and untangle the swordsman as he wanders through collapsing rooms, wrapping his air line around bits of wreckage. Sanji may not come here often, but the damn marimo should really recognize which one of them knows where they’re going. It’s certainly not Zoro. He tries to make this clear, rolling his eyes as he tugs at the swordsman’s arm, uncertain how well the human can hear through that helmet.

Scoffing, the sound echoing oddly through the helmet and the water between them, Zoro doesn’t act the least bit chagrined. Sanji swoops around behind him and gives the human a push, directing him through the crumbling remains of the ship. 

It’s dimly lit and strangely empty, though whether this ship was always so featureless or if the steep slant of the wreck tipped everything out into the deep, Sanji doesn’t know. He’s visited a variety of human shipwrecks, and most still have ruined decorations in the rooms, furniture at least, but only a very few spaces in the heart of this behemoth contain any sign of previous inhabitants.

Now, it’s home to hundreds of small fish, darting schools fleeing through any available opening as Sanji and Zoro pass through. A few juvenile sharks, one truly massive grouper, coatings of anemones and barnacles, but no signs of the human lives that made the ship.

Even their destination doesn’t feel _inhabited_ , deep in the sturdy hull of the wreck, but at least it isn’t so eerily empty. Swimming down a steep stairwell, rendered useless by the tilt of the ship, Sanji listens to the clunking of Zoro’s progress before passing through the final door.

Zoro jumps down beside him, tugging impatiently at his air line. Sanji wonders if the idiot will be able to hold his breath long enough to make it to the surface, if it tears, and concludes that his best bet would be to shove the human upward and swim as fast as he can in the other direction. It would take too long to drag Zoro out of the wreck, and Sanji’s not about to bring a corpse back to those people. A week or two out here while he recovers enough to swim back to more gentle seas will be better than facing their reaction if the swordsman drowns.

The line stays intact, and Sanji gestures at the door. It hangs crooked on its rusting hinges, but swings outward easily enough when Sanji lifts it out of the way.

Above them, the upper floor is partially rotten, letting a few shafts of sunlight into the hold. Enough to see, if only barely, the heaping pile of treasure settled at the lowest corner of the room.

Behind him, Zoro stumbles on the sloped decking, and Sanji fancies it’s shock at seeing the hoard. Mostly gold, a bit silty but untarnished, gleaming where the meagre bits of light touch it.

Unfolding his net, Zoro pauses like he isn’t sure where to start. Sanji can’t blame him, exactly, but he doesn’t want to spend any more time here than they have to, and so he shoves Zoro toward the treasure. This space is too dark, too enclosed; there are even darker openings on two of the walls, leading to parts of the wreck Sanji hasn’t explored, and the gaping doorways scream of danger. Maybe it’s just his instincts talking - don’t block yourself in, don’t swim into the darkness, keep to the open water where you’ll be safe - but there’s no good reason to linger here. Creatures that hunt in the dark love claustrophobic wrecks like this.

With a flick of his tail, Sanji goes to join Zoro as the human indiscriminately tosses bits of treasure into the net. Golden statues, much of it, heavily carved in a strange style Sanji hasn’t seen anywhere else, but there are chests of jewelry and baubles too, the wood nearly crumbling to the touch, and more practical metal cases containing who knows what. More than enough to choose from.

Sanji thinks about the figurehead, the way the massive gold face gleams strangely in the shadowed water. Swimming beneath the prow of the wreck to look at it was eerie the one time he tried it, and Sanji is not going to mention it to the humans. There’s plenty of gold here to satisfy them, and he doubts their little boat could even transport the enormous figurehead, with its stern expression and radiating suggestion of sunbeams.

Even though all of the treasure is piled gracelessly in the corner now, there are remnants of shelves and displays in the heap, broken bits of wood and glass breaking up the monotonous dull gleam. Sanji can’t guess which pieces were important to whoever built this ship, but a few of the objects catch his eye, the same ones that have drawn his attention each of the brief times he’s explored here before.

An empty frame, the curved forms of a human and a mermaid meeting in a circle that clearly used to hold a small object of significance, the setting in the center long empty. The motif of a bell, repeated across the surface of many of the decorated statues. A fist-sized golden cube resting in a nest of shattered glass, covered in writing Sanji cannot read, the script likewise reappearing on many of the other objects. It’s all very strange, even compared to the human artifacts Sanji has recovered from other shipwrecks.

Throwing the cube and a few other random pieces into the net, Sanji gestures at the marimo to hurry up, hoping his flicking fins don’t give away his own agitation. Every curious fish darting through the doorway or crossing through the sunbeams above them makes him twitch.

Pushing Sanji away, irritation clear in the set of his shoulders, Zoro ties off the net and jerks on the rope, clearly some kind of predetermined signal, as within moments it begins to pull away, dragging the heavy load back toward the surface. Zoro follows, shoving at it in an attempt to guide the unwieldy weight, but not before it jams against the doorway they came through with a _thud_ that reverberates through the entire room.

“Careful,” Sanji snaps, despite knowing that the human won’t hear him. Zoro doesn’t so much as look back as Sanji uneasily glances around them.

Something flashes in the darkness of the nearest doorway, stronger than the flickers of sunlight shining off the nearby fishes’ scales. At the same moment, Sanji feels static prickle along his skin, sharp and clinging as a shock travels through the water.

A giant eel bursts into the hold, electricity glittering along its orange-striped body. Choking down a panicked scream, Sanji darts over to the marimo and puts all his strength into shoving that stupid net through the door. Zoro turns to look at him and this time Sanji _knows_ the human’s flinch is shock, as he spots the creature speeding toward them.

“Go!” Sanji shouts, loudly enough that he thinks Zoro understands him this time. Either that or the message is clear anyway. The encumbered human doesn’t stand a chance against a predator like this, especially in such an enclosed space, and with no weapons to speak of. 

Flashing all his fins in a threatening display, Sanji darts to the side, attracting the eel’s attention. It opens its mouth, all needle-like hooked teeth, and another warning charge prickles through the water.

Scraping noises from above, so the defenseless human must be getting away. So _slow_ , much too slow to escape this creature’s den. Sanji is in no shape to fight a predator like this, but he can’t let it go after Zoro.

Sanji swims back and forth across the small room, baring his own teeth as the eel lunges at him, the force of its movement rocking him slightly as it passes. Not close enough to touch, but near enough that its paralyzing shock skitters along Sanji’s skin, sending a deep shudder through his body.

Another clumsy _thunk_ from the upper areas of the ship, and the eel turns its attention from the more difficult prey, sliding past Sanji to slip through the door. Following, Sanji tries to grab the end of its flared tail and has to let go immediately, the electricity that lances through his bones at the contact too painful to bear.

Clutching his numb hands to his chest, Sanji squeezes through a broken section of flooring, hoping to reach Zoro and head the eel off before it can attack the human. He finds the marimo kicking at a fallen piece of hull, jammed at an angle that prevents the humans in their boat on the surface from hauling the treasure through.

There’s no time for subtlety. With the most powerful blow of his tail that he can muster, Sanji breaks the beam, knocking Zoro through into the next room in the process, and feels half-healed muscles protest the strain. As much as it hurts, Sanji would rather set back his recovery than become some ambush predator’s dinner.

As Sanji spins head over tail from the force of his strike, the eel shoots up from the lower hall. Sanji can see Zoro turn to look, and can only hope the human has the sense to keep moving.

The eel lunges for Sanji again, and he barely manages to twist away from those wicked teeth. It’s too close to risk fleeing, so Sanji knocks its head as hard as he can with his tail, gritting his teeth in preparation for the shock.

This time he feels something tear, but the mundane sting is overshadowed by the electricity thrumming though him, making all his muscles seize in horrifyingly unfamiliar pain. The eel is equally stunned, twitching as it drifts away from the impact. Weakly regaining control of his tail, Sanji manages a few strokes toward the exit, and nearly strikes out again when he feels something yank him out of the shipwreck.

It’s only Zoro, gripping an oar port near the hole with one hand as he balances on the side of the wreck. His grip on Sanji’s arm is punishing, movements harsh as he shoves him upward. Above them, the net of treasure is already pulled up to the side of the boat.

Curling around himself, Sanji allows for a few moments of self-soothing as he drifts away from the ship. The lingering shocks slowly leave his body and Sanji gingerly stretches out, feeling sick when he sees a thin trail of blood seeping from the side of his tail.

He’ll just have to wrap it up again. There’s no undoing the damage, and Sanji doesn’t regret fighting to survive, or protecting Zoro. The wound twinges as he swims, but there’s no need to go too fast - watching Zoro swim laboriously up toward the boat is almost funny enough to make Sanji feel better about the whole encounter. At least until the human hauls himself over the side of the boat and Sanji floats up to rejoin them.

“What was that!?” Zoro snarls, dragging Sanji out of the water by his hair and holding a sword to his throat. His arms don’t so much as waver, muscles bulging with perfect control.

Sanji yelps, scrabbling at his hand, trying to get a grip to take some of the weight off his hair. He ends up clinging to Zoro’s shoulders, tail flailing against the side of the boat. “Fuck off, shit-swordsman, let go of me!”

Beyond him, Nami, already busily fawning over the treasure, drops a heavy statuette, and Usopp cries out in alarm. Sanji can’t spare them a glance, not with their swordsman’s blade at his throat.

“Electric eel,” Sanji gasps. He didn’t get a good enough look to tell which subspecies, but he’s never seen one that large no matter what.

“Couldn’t have said something about that, if you’ve been here before?” The swordsman demands, shaking him against the boat.

“Zoro -” Nami begins, but he turns to her with such a glare that she falls silent, a storm brewing in her expression.

Sanji doesn’t bother to explain that of course he would have said something, if he had ever seen that creature here before. He’s only spent a few hours total near this wreck, and never explored the truly hidden areas.

“Got the treasure, didn’t we?” Sanji hisses. Zoro glares back, not moving his sword at all.

“Zoro -” Usopp pleads, peering over the farthest seat. “What happened -”

“Let Sanji-kun down!” Nami shouts, abandoning the treasure to grab Zoro’s arm. “Gods above and below, Zoro, try talking first, will you?”

This time Zoro does drop him, and Sanji catches himself on the side of the boat. “I didn’t know,” he says, uncertain and uncaring of whether the swordsman even heard him.

“Like he said, we got the treasure, so what’s the problem?” Nami continues. “You’re both fine.”

“Barely,” Zoro mutters, scowling down at Sanji. “Think curly-fish fucked up his tail again.”

Usopp scrambles over, peering into the water. “Did you?”

“Next time say that first!” Nami chides, letting go of the marimo. “What happened, Sanji-kun?”

“Got attacked,” Sanji says, nonplussed by Zoro’s reasoning. “Might’ve strained something.”

Nami sighs, casting a reproachful look between the two of them. “Let’s get back to shore and take a look at that, Sanji-kun.”

They raise the anchor and sail the little boat back to the tiny island, where Luffy is sitting despondently in the sand, pouting and refusing to meet anyone’s eyes. “I can’t believe you left me behind, I’m the _captain_ ,” he grumbles, before jumping up to rummage through the treasure.

“Don’t you dare break anything,” Nami calls, tying everything down. Zoro merely huffs, ruffling Luffy’s hair as he jumps off the boat.

Lingering a bit offshore, Sanji tries to take stock of himself and guess how bad it is. Hard to tell, with the lingering soreness from the eel’s electricity, but there isn’t too much blood on his bandages. With a sigh, he drags himself up onto the slip of beach.

“Is he really your captain,” Sanji asks, when Zoro stomps over to him.

The swordsman blinks. “Of course he is.”

“Right.”

Without another word, Zoro hauls Sanji over his shoulder and dumps him in a shady patch of sand, out of the others’ immediate range. “Shouldn’t have agreed to do this if you couldn’t handle it, curly. Listen to Law next time, he’s a pain but he knows his stuff.”

“Are you paying any attention, shitty swordsman? We got the treasure, so I’d call it a success!”

The two of them glance back to the boat, where Luffy is whining to Nami about how much he wants a really big statue, and not this kind of boring treasure. Sanji does not understand these people at all.

“I meant that monster,” Zoro growls.

“It turned out _fine_ ,” Sanji insists. “Why do you care, algae brains? Would’ve gotten me out of your hair.”

The human glares at him but starts unwrapping Sanji’s bandages anyway, effectively trapping them both into this conversation. “Look. I can’t watch out for you and Luffy at the same time, but you’re clearly too reckless to take care of yourself.”

“Reckless?!” Sanji protests.

“Shut up. I don’t wanna see you dead, stupid fancy fish, but I don’t want you sticking around Luffy, either.”

“Do you ever make sense?” Sanji demands. He’s really not seeing the connection.

Zoro sighs. “Luffy always gets mixed up in people’s shit. It’s like he can tell who’s got the worst trouble, and he _always_ gets in over his head. You’re obviously the same, and I’m sick of watching my captain throw himself in front of a blade someone else is too foolish to run away from.”

“You don’t know anything about me,” Sanji mutters, watching Zoro’s careful hands wiping blood off his tail instead of the swordsman’s dark expression.

“I know you’re in trouble,” Zoro says plainly. “Know you’re lying about what happened to you. Know it must be bad, ‘cause you’re a tough bastard for such a prissy fish, and I know Luffy will help you if you tell him about it. So you better start taking better care of yourself, because if we get mixed up in your mess and it comes down to you or Luffy, I won’t hesitate.”

A thought occurs to Sanji, and it’s this or start asking why Zoro seems so concerned about Sanji’s problems, so he just says it. “Are you in love with him?”

“In love with… who?” the swordsman blankly asks.

“With _Luffy_.”

Zoro stares at him for a long moment, before snorting so hard he almost topples over. “That’s ridiculous.”

“Not all love looks the same!” Sanji says. It’s not such a reach, after that speech. “It would make sense, with how protective you are of him!”

“He’s the most important person in my life,” Zoro responds, cheeks darkening as he ducks his head to start re-bandaging Sanji’s tail. “But it’s not like that.”

“Really?”

“Really,” Zoro snaps. “We’re not like that. _He’s_ not like that.”

“Like what?” Sanji presses. The more Zoro talks, the less it sounds like _no_.

“You’re the one who just said not all love is the same,” the swordsman impatiently says. “I love him, sure, and he loves all of us, but it’s not _like that_. Luffy doesn’t want that kind of romance stuff.”

Sanji can’t imagine _not_ wanting romantic love, but he supposes he’s not the best person to talk about it. After all, he’s only known his mother’s love for her children, love that _killed_ her, and maybe he would be happier now if she had loved him a little less. Maybe he’d be like his brothers, and not feel the lack. 

“Why’s it matter, anyway?” Zoro asks.

Why indeed. Because Sanji has _standards_ , that’s why, and he would never knowingly try to seduce someone who’s taken. Not that he can say that, since he’s not even sure if the algae-brained human even realizes that’s what Sanji has been doing. “It doesn’t. Just, if you were with him, I’d…” Apologize? Give up on trying to protect himself that way? “Stop. A few things.”

“What kind of things?” The swordsman looks like he already doesn’t like the answer, his familiar scowl settled firmly on his face.

“Nothing important,” Sanji deflects. “Just, you know, if someone has a significant other, sometimes it’s a dick move to -”

“You _were_ flirting with me!” Zoro blurts.

“What?” Sanji yelps. “Of course not, who would look twice at a clumsy, algae-brained -”

“You totally were! All the lazing around and - and _eyelashes_ , why were you doing that?!”

“Just to see how long it took you to notice,” Sanji mutters, trying to brush the issue off. The swordsman doesn’t seem angry, not really, but Zoro sure isn’t happy about it, either.

Zoro narrows his eye at him, quieting. “You’ve been doing it since we found you.”

“So?”

“Hard to believe you’d be set on messing with me from the moment we met, given how much of a wreck you were.”

Involuntarily thrashing his tail across the sand, Sanji avoids the human’s cutting gaze. “I was trying to make you see me as a _person_ , instead of a _creature_. Didn’t feel too safe around you, after that introduction.”

“Of course I see you as a person,” Zoro retorts, affronted. “A person I hate, sure, but - wait. Were you - were you trying to trade sex for your _life_?!”

Sanji doesn’t know what to do with that expression of vague horror. His little plan is backfiring in a huge way. “Might’ve thought about it.”

“You thought - what were you thinking?! That I’d leave you to die if you didn’t -”

“Your precious captain threatened to _eat_ me,” Sanji cuts in. “I woke up tied down and had to watch him roast a chunk of my tail. Pardon me for thinking I needed to ingratiate myself somehow.”

The algae-brained swordsman can’t get it through his thick skull, apparently. “But that’s -”

“I didn’t have anything else to offer,” Sanji continues. Might as well make it as clear as possible. “Some humans like that. Exotic opportunities.”

Letting out a tightly controlled breath, Zoro sits back on his heels to stare at Sanji. “I would never take that kind of advantage -”

“It’s not like it matters.” Sanji shrugs, trying to look indifferent. “You’re not interested, or too stupid to realize I was practically throwing myself at you, or whatever, so it’s nothing -”

“I would never,” Zoro repeats.

“I thought you were going to kill me,” Sanji says.

They stare at each other. Zoro leans in just enough to tie off Sanji’s fresh bandages, gentle despite his rough hands. The shrieking and laughing from the human’s small boat sounds very far away.

“You don’t think that anymore?” The swordsman finally asks.

“No,” Sanji answers, realizing as he says it that it’s true. Something about this conversation has changed his mind, even with the memory of Zoro shaking him against the side of the boat still fresh on his bruised skin. Maybe his sense of ease around these humans isn't so unreasonable.

“Luffy wasn’t really going to eat you,” Zoro offers, looking away.

“Not sure I believe that.”

“Okay, fine, that’s fair, but I’m still not the type of man who would just _kill_ an injured stranger in cold blood, or hold that over you in exchange for - for favors. Like that.”

“I get it, you’re not interested,” Sanji says. He’s just about over the novelty of the marimo’s stammering, and this entire topic. “Knew it was just as likely that you wouldn’t have that kind of taste. Still had to try.”

“This isn’t about _taste_ , curly, it’s about basic decency -”

“What’s not about taste?” Luffy asks, popping up over Zoro’s shoulder. “Nami says we have enough gold to get barbecue when we get back, you guys did great!”

Zoro sighs, reaching up to ruffle Luffy’s hair. “Doesn’t matter. Guess the witch is happy, huh?”

“Yeah! Hey Sanji, do mermaids eat barbecue? What kind of meat do you like?”

“I’m not picky,” Sanji responds, shaking off his bemusement as Nami walks up behind the two. “Is the treasure what you wanted, Nami-swan?”

She pauses a step away, surveying them all with her hands on her hips. “How’s his tail, Zoro?”

“Not so bad,” the swordsman shrugs, “but we should probably still take him back to Law.”

Nami nods, serious for another moment, and then throws herself at Sanji, squeezing him into the tightest hug he’s ever experienced. One of few, but he’s sure this would compete no matter how worldly he was.

“It’s amazing, Sanji-kun! We’re _rich_ , this is definitely enough to pay Franky for the ship -”

“- and MEAT, right? Nami, you promised -”

“- and to feed this idiot, yes, Luffy, we’ll get you some meat. It’s even enough to pay for your medical bills, I bet,” she finishes, loosening her grip enough to give Sanji a wink.

“We all know Law and Chopper don’t charge,” Zoro mutters.

“I’ve never seen so much gold,” Nami dreamily says, ignoring the swordsman completely. “We’ll leave first thing in the morning, and take you to see Law before getting it exchanged.”

“And getting -”

“And getting your barbecue, _yes_ , Luffy.”

It’s barely midday, so once Luffy is appeased and Nami is done organizing the treasure, it’s a rather slow afternoon. Usopp produces some fishing gear, Zoro takes a nap, and Sanji heads back into the water to see if he can’t catch something better than a few shellfish to eat tonight.

He’s getting used to swimming with the pain. The twinges hardly bother him as Sanji follows the flow of water through the reef, passing over the hiding places of lobsters and slow-moving conch for now.

Taking his time, Sanji stalks a large grouper along the deeper edges of the reef. It’s not as huge as the one haunting the shipwreck, but Sanji still feels confident that it will feed a handful of humans.

Yonji might chase it down and rip out its gills. Niji would thrash it to pieces right here on the reef. Ichiji usually orders one of the others to finish a kill, but failing that, could simply snap the fish’s spine like it’s nothing, more often than not tearing the creature right in half. Blood in the water, calling every predator for miles around, and none of them would dare challenge Sanji’s brothers for the meal.

Sanji glides across the coral until he has a clear shot, and stuns the grouper with a quick blow of his tail. Over in an instant, and even though all the smaller creatures on the reef scatter at the movement, they flow back into their normal lives in mere moments. Dragging the fish behind himself, Sanji leaves the rest undisturbed as he returns to shore. 

The humans have a boning knife in their kit, and Usopp keeps Luffy entertained while Sanji prepares the fish. He still can’t do much more than a simple roast, but Sanji is determined to make it perfect. Maybe he’ll get a chance to show these people what he can really do, before they sail away in their new ship.

Over dinner, Luffy and Usopp demand all the details of their treasure diving, Luffy pouting over being left behind while Usopp listens in fascinated horror.

“You got attacked by an electric eel?” the coward exclaims, gripping the knees of his overalls tightly enough to strain the fabric. “Well, the Most Talented Treasure Hunter Usopp has fought off entire nests of eels, and worse creepy crawlies, but I’m sure that was terrifying, for you!”

“Damn thing was practically the size of that fucking sea dragon by Vivi’s place,” Zoro growls, tearing off a bite of fish. He doesn’t need to be so rough; the fish is flaking perfectly, if Sanji does say so himself, tender and piping hot. “Never seen an eel so big.”

“You’ve seen a sea dragon?” Sanji asks. It’s a comical exaggeration to compare the electric eel they fought to a sea dragon, but the creature sure _felt_ huge in the cramped wreck.

“Yeah!” Luffy shoves half his plate into his mouth, talking around the food. “We said ‘bye to Vivi, and aaalllll these Navy ships were in the way, but a HUGE sea dragon popped up and nobody knew what to do, but Nami’s the best navigator in the world and we got away!”

Nami shudders, looking up from the chest of jewelry she’s sorting through. “I hope we never see one again.”

“But it was so cool! Hey, Sanji, haven’t you seen one? You live in the ocean! Dragons live in the ocean, so you’re like neighbors!”

“Not all dragons live in the ocean,” Nami comments under her breath. She picks a delicate necklace out of the chest and smile, fastening it around her neck.

“I have,” Sanji confirms, once he can see through the hearts filling his vision at her beauty. He’s still shocked these humans did, though. “Only once, and I was down pretty deep, hunting tuna over one of the trenches.”

It’s the kind of experience that stays with you. Sanji will never forget seeing the enormous, sinuous shape gliding below him, rising out of the trench and disappearing into the vast emptiness of the open ocean. Sea dragons may be the most common type of dragon left these days, but it still feels like encountering a legend.

“Surprised it didn’t think _you_ were a tuna and snap you up,” Zoro idly says. 

Sanji doesn’t like the way Luffy’s attention shifts to his tail, drooling. “Surprised your shitty boat didn’t capsize, if you were so close.”

Zoro grins, all teeth. “Guess it liked us.”

Snorting at the ridiculousness of that idea, Sanji listens with half an ear as Luffy chatters on about the people and creatures they’ve met. Between his endless energy and Usopp’s tall tales, the conversation lasts until well after sundown, when Nami shoos everyone off to sleep.

They’re all eager to leave the next morning, the humans clearly feeling caged by the tiny island. Sanji understands, although he keeps the thought to himself as Zoro helps him into the equally tiny tank on their boat. Seems there’s no way to keep everyone happy; humans aren’t suited to the open ocean Sanji prefers, and he’s eager to bid this lukewarm tank goodbye forever.

“The prevailing winds are going this direction,” Nami says, drawing a finger along her map as she charts their course. “Anything we should look out for, Sanji-kun?”

He shakes his head, eyes tracing the path back to the human’s home island, and taps the map. “It might be faster to catch this current, but you would have to sail out of the way to reach it.”

The current in question would pull them past a wide area of shallow seas, the stretch between two islands that lie not far from Sanji’s family’s territory. Dominated by seagrass and grazing herds of sea mammals, it’s a pleasant area this time of year. And, if Sanji isn’t mistaken…

“Miss Nami,” he hesitantly asks, “Actually, if it wouldn’t trouble you, could we take this route?”

“Why?”

“I’m the captain, you can’t decide without me - where are we going, Sanji?”

“Someone I haven’t seen in a while… they should be near here, in this season.” Sanji doesn’t _need_ to hide this from them, but he can’t help wanting to keep the details to himself, in case they’re going to reject his request outright. Even though they’ve been friendly and agreeable, he’s used to keeping this relationship a secret. “It wouldn’t take long.”

Nami holds Luffy back with a hand to his face, and peers between Sanji and the map. “As long as we still get back before dark, I don’t see why not.”

“Sanji’s been a big help, so we’ll help Sanji!” Luffy declares, as if his input has any sway in Nami’s planning.

“Thank you so much, mellorine!” Sanji chirps. He can hardly believe it was that easy.

“Better not be another freaky monster,” Zoro says, but his smirk is teasing as he shoves the boat out into the water.

“I wouldn’t get myself trapped in this tank if I wanted to lead you into a predator,” Sanji snaps back. “And I certainly wouldn’t put Nami-swan in danger!”

“Or the rest of us, right?” Usopp asks.

Zoro snickers and Sanji rolls his eyes as Luffy leans out over the side of the boat, hat blowing off to catch on the string around his neck. Usopp sighs, like he knows he won’t get an answer, and wouldn’t like it anyway.

Curling up in the tank, Sanji lets himself relax as the humans sail their little boat off the reef. Not too long ago he thought he’d never see the old man again, but now they’ll get there within hours, if Zeff is still sailing the Baratie along the same old patterns. 


	6. Fate, Like Waves

The little boat drifts out of the current, Nami’s deft hands on the tiller keeping their course steady. Peering over the edge, Sanji watches the deep blue of the ocean brighten, until they’re sailing over shallow fields of seagrass, vivid green interspersed with patches of bare white sand.

It’s almost impossible to keep Luffy in the boat, as they cross paths with herds of sea cows and other gentle herbivores. Nami is stepping away from the tiller to tie their captain’s hands around the mast when the Baratie finally appears on the horizon.

“What’s that?” Luffy shouts, forgetting about the pair of manatee trailing beneath the boat as he jumps to the prow. “Nami, Nami, let’s go there!”

“That what we’re looking for, fish-cook?” Zoro asks, grabbing Luffy by the back of his vest before he can fall into Sanji’s tank.

Sanji nods, a bit shy now that the Baratie is in sight. It looks the same as always, the weathered fish head and wide platforms bright with fresh paint as they draw closer. 

“What is it?” Usopp queries.

“A restaurant,” Sanji mutters, ducking just in time to avoid Luffy’s excited flailing.

“A restaurant!? Do they serve MEAT, I want meat if I can’t eat one of these cow things -”

“You know this place, Sanji-kun?” Nami asks. 

He nods. “Uh. But, I don’t want to be seen…” He’s used to sneaking up underwater to talk to the old man, not sailing in during the day where anyone could see. “The old geezer - erm, the head chef. He knows me.”

“Head chef!?”

“We’ll get you something to eat, Luffy,” Nami snaps. “And that’s fine, Sanji-kun. If you stay on the boat, we can ask this - what’s his name, the head chef?”

“Chef Zeff,” Sanji mumbles.

“Chef Zeff,” she repeats. “You want to talk to him, right? We’ll let him know.”

As Nami steers them into a docking spot, Usopp throws a tarp over Sanji’s tank. None of them even ask why Sanji doesn’t want to be seen, and Zoro barely looks suspicious as he rolls his eye.

“Guess I can understand why you don’t want to splash right up to a human restaurant,” the swordsman mutters, laying a hand on the edge of the tank where Sanji can just see beneath the tarp. “Be right back, fish-cook.”

It’s not a particularly busy day, but the bustling noise of guests and Zeff’s chefs is still alarming, as Sanji waits with bated breath in the small dark space. He’s always free to swim away in an instant, when he comes here. The pirates could still decide to sell him, and it would be easy, here; even though Sanji knows that Zeff wouldn’t let any of the chefs buy him, this restaurant attracts gourmands from all the nearby seas, and there’s certainly someone here who would want a chance -

“You’re lucky I’m in a generous mood, rowdy kids,” a gruff voice says, just as Sanji is convincing himself that he should take the chance and get overboard. Even if someone sees, he’s too fast to catch if they have to unmoor their boat first -

Hearing Zeff’s voice calms him down instantly. Peeking out beneath the tarp, he can see familiar chef’s whites, and an even more familiar peg-leg.

“We’re not being shifty for the fun of it,” Zoro mutters.

“Looks clear,” Nami sighs, her pretty human legs coming into view. “I’m going to take this off, okay, Sanji-kun?”

She doesn’t wait for his response, peeling the corner of the tarp back enough for Sanji to prop himself up out of the tank. The look of pure surprise on Zeff’s face turns to suspicion in an instant, and he steps between the boat and the pirates, wooden leg clacking harshly on the dock.

“What are you lot doing with my little eggplant?” Zeff growls. Zoro looks startled enough by the old man’s fire to take a step back, and Nami raises her hands in front of herself.

Sanji is so relieved he could cry. Somehow, seeing the old man really makes him feel like he’s going to survive, like all the kindness the pirates have shown him wasn’t a lie.

“Shitty geezer,” he says, having to stop and choke down a sniffle. “Old man. It’s okay, they’re fine; it’s a long story, but -”

Zeff leans over the side of the boat, critical gaze assessing every injury on Sanji’s body, and he clocks Sanji upside the head. “You need to be more careful, eggplant!”

“It was just sharks -”

Zeff shakes his head, glowering at Zoro and Nami over his shoulder before turning that frown on Sanji. “Was it those brothers of yours?”

Sanji freezes. He’s never told Zeff about Ichiji and the rest, not even after they tied him up beneath the Baratie for months and Zeff barely fished him out before he starved to death -

“You sister came by,” Zeff gruffly continues, and Sanji’s head spins. “Told me a few things to pass on to you, if you showed up here.”

“Brothers?” Zoro growls.

“Sister?” Nami asks.

“Reiju was here?” Sanji manages, feeling like his grip on the edge of the tank is the only thing tethering him to reality.

“Should’ve told me your home life is such a mess, shitty eggplant,” Zeff chides. “The boys and I would’ve done whatever we could. Hell, Patty and Carne were ready to go out looking for you, when you didn’t show up for the weekly menu change.”

“But - they don’t -” They don’t _know_ , they can’t know, Zeff is the only human Sanji has ever been able to trust -

“Not nearly as sneaky as you think you are,” Zeff interrupts, a smile twitching at the corners of his mouth making his moustache wobble. “Of course they all noticed, the way you zoom around trying to see everything. Told ‘em you’re a shy little anchovy, not to scare you away.”

Sanji has spent so many nights swimming around the Baratie, hiding from all the chefs and guests, desperate to watch as much as he can… He thought Zeff was the only one to see him, after the first time the old man came out after close to teach Sanji a few things. He’s made it every week like clockwork since, coming to learn whatever Zeff can teach him from the outer deck, ever since he was a child. It was the one bright spot in his life after his mother died, and knowing that the rest of the chefs knew, but respected his fears, makes Sanji feel even more secure. He sniffles, avoiding the raging curiosity on Nami and Zoro’s faces.

“Not shy,” Sanji mumbles. “You try being half a fish, and watching what you all do in this place. You’d keep your distance, too.”

Zeff ruffles his hair and scoffs. “Nothing to worry about here, little eggplant.”

Sanji really is going to cry. He hasn’t cried in front of Zeff for years, not since he nicked a finger cutting ghost peppers and got some in the cut -

“What’s going on here?” Nami demands.

“Eggplant’s been coming here to learn about cooking since he was barely a little minnow,” Zeff grumbles. “Apparently the little shit didn’t think he could trust us to take care of him. Had to learn about his shitty family when that sister of yours showed up the other night, and let me tell you, idiot eggplant, that woman is twice the man you are -”

“Why did Reiju come here?”

With a deep sigh, Zeff glowers around the docking area. “Not gonna stand here and talk all afternoon,” he grumbles. “You, with the scars, bring the eggplant around back. Bet we’ve got something to put him in stored somewhere.”

Stomping off, Zeff leaves the two pirates and Sanji staring after him in flabbergasted silence.

“I don’t take orders from you,” Zoro mutters.

“Better do as he says,” Nami finally says. “You’ve got some explaining to do, Sanji-kun.”

“Yes, Nami-san,” he meekly answers. Better her reproachful gaze than Zoro’s dumbfounded glare.

“Knew it wasn’t a shark,” Zoro says, reaching for Sanji. 

Wrapping his arms around the swordsman’s neck, Sanji lets Zoro get an arm under his tail and sighs into the human’s neck. “You can’t blame me for keeping a few secrets.”

“But I want to hear about them later,” Zoro rebuts, holding Sanji a little closer than strictly necessary as Nami leads the way around the back of the Baratie. “These brothers of yours.”

“I don’t want to talk about them,” Sanji says, feeling the rumble in Zoro’s chest as the human growls at that answer.

“Argue about it later,” Nami orders, peering around the corner of the back deck before waving them forward. “But you’re going to tell us, Sanji-kun.”

The little huff Zoro lets out isn’t quite a laugh, but his breath is warm against Sanji’s skin and his grip is gentle as they quiet down. They come in the back of the kitchens; Sanji has been here a few times, when he let Zeff coax him out of the water with the temptation of learning the old chef’s many tricks. It’s strange to see in the daylight, even though Zeff seems to have shooed the other chefs out. The old man is standing next to a massive pot, arms crossed over his chest.

“Toss him in,” Zeff directs, whacking the side of the pot with a wooden spoon. It makes a dull thunk, and Zoro balks. “Don’t be stupid, swordsman, it’s just salt water.”

“This is still pretty fucked up, old man,” Sanji says, once he’s into the pot. It’s large enough for his tail to curl up without being too cramped, the water well above his hips. Aside from the imagery, it would be pretty comfortable.

“I’ll get the others from the dining room,” Nami sighs.

Ignoring Zoro entirely, Zeff frowns at Sanji. “What happened to you, little eggplant?”

The swordsman shifts his feet, eyebrows pulled downward. Sanji almost feels bad for the human, given what Zeff would do to him if Sanji tells the whole truth.

“Turned out okay,” he mutters, avoiding Zeff’s eyes. 

Zeff obviously doesn’t believe him, but Nami brings Luffy and Usopp through moments later, and Sanji shrugs.

“Got in a fight with my brothers, and they cut me up a little,” he says, keeping the details light. “Tried to escape through a jellyfish bloom, got a few stings. This lot pulled me up, thought I was some exotic fish. They agreed not to sell me off or eat me -”

“But Sanji tastes good,” Luffy says under his breath.

“What?” Zeff growls.

“He just means he’s had sailfish before, calm down,” Sanji hastily corrects. It’s only a small lie. “Anyway. They fixed me up, brought me to see a human doctor, and I offered to help get them some treasure. Ran into an electric eel, knocked my recovery back a bit, that’s all.”

“All,” Usopp mutters.

There are other marks that story doesn’t explain away. Rope burns, hand-shaped bruises, a few thin welts from Usopp’s bizarre net. Sanji knows Zeff sees them all, but the old chef lets Sanji have the evasion.

“From what your sister told me, those fish you call brothers did more than cut you up, eggplant,” Zeff says disapprovingly.

“When did Reiju come here?” Sanji pleads. “Come on, old man, tell me about my sister.”

“Never would have thought a minnow like you could have such a fancy lady in the family, eggplant,” the old chef says. “‘Course, always figured you didn’t have any family. Thought that was why you always looked so roughed up, nobody to look after you out there in the blue.”

“Spare me the guilt trip,” Sanji groans.

“Well, imagine my surprise when a stunning lionfish swims up to my restaurant, looking for my little anchovy,” Zeff grumbles.

“Your sister is a lionfish?” Usopp blurts. “How’s that work?”

“Yeah, it’s not a straight-line thing,” Sanji dismisses. “What did Reiju come here for? She doesn’t talk to humans.”

Still, Sanji can easily imagine Reiju popping out of the ocean and demanding to talk to whoever is in charge, in that imperious way of hers. Even without her venom, no one would ever be willing to cross her.

“Should kick your ass for making a lady worry like that,” Zeff says, stomping his wooden leg. “Didn’t seem half concerned about showing herself to humans, just wanted to know if we’d seen you lately.”

Sanji doesn’t bother asking how Reiju knew to look for him here. It’s more surprising that she never came by to threaten Zeff and the others before.

“Told her you hadn’t shown up for menu change,” Zeff continues, a brief frown betraying his own worry. “The lady explained what you said, eggplant - that you’d gone out with those damn brothers of yours, and never come home.”

“I - I’ll go see her right away,” Sanji promises. “I’m fine, anyway, no one has to worry about me -”

Zeff shakes his head, a pitying look on his face. “That’s what she said you’d want. Told me not to let you go home, if I saw you.”

“What do you mean?!”

“They think you’re dead,” Zef bluntly announces. “Your lady sister said not to come back. You’ve got a chance to be free of them, eggplant, and she wants you to take it.”

Sanji freezes, gripping the edge of the pot, and gapes. The others are just as surprised - Luffy strangely quiet, Nami and Usopp’s eyebrows up to their hairlines, a dark storm crossing Zoro’s expression - but he can hardly spare them a glance.

“Never go home?” Sanji breathes. Sure, he’s daydreamed about running away, even tried it a few times as a child. After a day or two Judge always sent people after him, and Sanji never had the nerve to go far. He doesn’t know where to go, how to survive on his own; he couldn’t risk Zeff’s restaurant by hiding here, he didn’t want to leave Reiju behind forever… but if they think he’s dead, if Judge won’t send his soldiers after Sanji this time…

“Doesn’t sound like much of a home, kiddo,” Zeff says.

“It’s not.” The words fall from his mouth without his control, too raw in this room full of near-strangers, but the empathetic warmth in Zeff’s gruff frown makes it worthwhile. “I hate them.”

“Sanji can be my cook!” Luffy cheers, all his pent-up enthusiasm packed into the exclamation after being quiet for so long. “I told you, Sanji! Being a pirate is great!”

“If you really don’t have anywhere else to go…” Nami hesitantly offers. “You’ve been very helpful, Sanji-kun.”

“It’s decided!” Luffy declares.

“Hold on, shitty kid, I haven’t agreed -”

“There’s no stopping him,” Zoro interrupts, barely holding back a smirk. “Especially not now he knows you’re at loose ends, curly-cook.”

“Looks like you’ll be fine, eggplant,” Zeff congratulates him, with a heavy hand on Sanji’s shoulder. “Can’t fit a tank big enough for you on this damn ship, anyway.”

“As if I’d let you keep me in a tank,” Sanji hisses, swatting his hand away.

“As if anyone _could_ keep you in a tank,” Zoro comments. “Bet when you’re healed up you’ll be able to shatter glass with that tail.”

“Speaking of healed,” Zeff growls, “I better see you lot back here for next week’s menu change, and my eggplant better be looking less like you trussed him up for a fish market, you hear me? Little anchovy’s still got a lot to learn.”

“Sir, yes, sir,” Usopp gulps.

“Will you still have meat next week?” Luffy asks suspiciously.

Zeff glares at them, and Nami claps her hands together with a sigh. “Well, everyone,” she brightly says, “daylight’s wasting. If we’re going to get Sanji-kun back to Law today, we should head out.”

Luffy is starting to eye the storage cupboards and ingredients left out in the kitchen, so Sanji can only agree, even if he’d like to spend more time with the old chef. Zeff won’t have much patience for Luffy eating him out of house and home, no matter how well they can pay now.

He nods, Zeff nods, Zoro rolls his eye; Luffy reaches for a bowl of uncooked potatoes, and Nami pushes him at Usopp. “Go get the boat ready. I’ll make sure no one is outside, so say your goodbyes, Sanji-kun.”

“I’ll see you soon, no need to get sentimental, little anchovy,” Zeff grumbles.

“Like I would, shitty geezer,” Sanji snipes back, imperiously gesturing Zoro over. “Help me out of this stock-pot before the old man turns me into soup, marimo.”

“Not enough meat on those bones,” the chef retorts. “Make sure he eats, swordsman.”

“Let’s just go, fish-cook,” Zoro says, reaching for him with an uneasy glance at Zeff.

Sliding his arms around Zoro’s neck, Sanji makes sure to splash the swordsman and Zeff with lukewarm salt water. Funny how natural it’s gotten, trusting the swordsman to carry him. The old man gripes, and Zoro barely waits for Nami to give them the all-clear before stomping out the door.

“Didn’t realize we were meeting your dad.”

“He’s not my _dad_ ,” Sanji sputters. “In case you missed it, I’m _running away_ from my biological family -”

“Sure seems like he wants to look after you,” Zoro says, peering down at Sanji. “Little eggplant, baby anchovy minnow, all that.”

Sanji snarls and thrashes his tail, but he can’t refute that. No one but Zeff ever tried to look after him at all, not since his mother died. Reiju watches out for him, but all she can do is stitch up the cuts.

“He interrupted the kitchen in the middle of the day for me,” Sanji murmurs. “Didn’t realize he cared so much.”

“‘Course he does, if you’ve been coming around here for so long,” Zoro retorts. Sanji doesn’t protest. Hard as it is to imagine that the human chef would care so much about a flighty merchild, he can’t deny that Zeff’s gruff behavior is affectionate.

The thumping of Zoro’s heartbeat where their chests are pressed together blends in with the dull sounds of the swordsman’s boots on the deck, and the waves lapping at the hull of the Baratie. Sanji takes in the sights, so different from this vantage, in the bright sunlight instead of furtive nighttime visits. Maybe they’ll come back in the daytime, and he can introduce himself to all the other chefs he knows so well from observation.

“We’re still on track to make it to Law’s before dark,” Nami announces as Zoro jumps into the boat. “Get that sail up!”

Once the boat is underway, she turns to Sanji in his tank, a curious tilt to her head. “How did you meet Chef Zeff, Sanji-kun?”

“It was when I was little,” Sanji tries to deflect. “I wanted to learn how humans cook.”

“That’s so cuuute,” she coos, before snapping a hand down beside him. “But why a floating restaurant? How’d you even find the place? There are plenty of seaside restaurants on every island around here.”

“I was hiding from my brothers,” Sanji sighs. Across the boat, Zoro’s shoulders stiffen. “They used to… well, we never got along, Nami-swan. I would swim out to hide in the seagrass, and the old man has always sailed the Baratie around here.

“I thought I was hiding well enough, but apparently he knew I was there from the first night. I would peek through the rails, try to see into the dining room or the kitchens. After close, Zeff came out to find me, and once I stopped swimming away at the first sight of him, he started to teach me things.”

“That’s where you learned to cook so well,” Nami says, looking satisfied by the explanation.

“What did he mean when he said you looked rough whenever he saw you?” Zoro demands. “That these brothers you won’t talk about?”

“Yeah,” Sanji bitterly concedes. “Like I said, shit-swordsman, we never got along. Guess the old man realized it wasn’t just me being a clumsy kid after he found me tied up under his restaurant.”

“Tied up?” Usopp squeaks, peering around the mast.

Sanji splashes a little, avoiding everyone’s eyes. He’s not that weak child anymore; most of the time, he can give his brothers as good as he gets, these days. “Niji’s idea,” he mutters. “Yonji was already strong enough to drag me halfway across the damn ocean, and one of them must have seen me visit the Baratie. Ichiji told me they’d let me free if I promised never to go anywhere near humans again, but I’ve never given in that easily.

“Said if I loved them so much, I could stay with them forever,” Sanji continues, affecting a careless shrug. “They got me all twisted up in some old fishing net, fastened it under the hull. Zeff found me there when he was checking for barnacles.”

“Sanji-kun…”

“How long?” Zoro growls.

“What’s it matter?” Sanji demands. “It was a long time ago, marimo. They’ve done plenty of other shit since.”

“How long?”

“Couple months,” Sanji bites out. “Hard to keep track of time like that. Managed to catch a few fish that were stupid enough to swim close, but I was delirious when Zeff pulled me up. Don’t really remember much of it.”

The swordsman cracks his knuckles, and for a moment Sanji feels that same visceral fear he experienced when these humans first pulled him up. Zoro looks positively deadly, and Sanji almost wants the man to meet his brothers, just to see what he’d do.

Luffy hops over and plonks his hat onto Sanji’s head. “We’ll deal with Sanji’s brothers,” he brightly declares. “So don’t worry! If we see them, I’ll knock ‘em right out of the ocean!”

“We can talk about it once we get to Law,” Nami gently says. “Luffy’s right, Sanji-kun. We’ll help you.”

“What did I tell you,” Zoro grumbles, but he still looks angry on Sanji’s behalf as he scowls at him. “Right into the worst trouble.”

They don’t know the half of it, don’t know about Judge and all his horrible ambitions. Still, Sanji believes them. In this moment, he completely trusts that Luffy will fight every one of the Vinsmokes on his behalf.

It’s a comforting feeling, and terrifying. If Sanji is lucky, his family will never realize he’s alive, and these carefree humans will never have to make good on their promises. There’s no chance they could stand up to the might of the Germa kingdom.

After dragging that history out of him, they mostly leave Sanji alone as they sail. Usopp sits with him and tells stories while he repairs a few ropes, Nami checks in to show him the map, Luffy perches on the edge of his tank and eats his mid-afternoon snack, and part of Sanji’s too. Zoro takes a nap beside the tank and eyes Sanji as he settles in, almost like he’s making sure Sanji isn’t upset by the morning.

“It’ll be fine, shit-cook,” he mutters. “And if you really don’t wanna come with us, Law will help you out. Luffy will understand.”

“I’m not worried about it,” Sanji grumbles back. “Go to sleep, idiot marimo.”

“You’re not, huh?”

It's a lie they're content to share.

~o~O~o~

When they get back to the doctors’ cave - and Sanji _swims_ in this time, instead of being carried, and isn’t that a joy - Law is already sitting in the entry area with a serene, dark-haired woman. She looks up with a smile, neatly side-stepping Luffy as he tackles Law.

“Robin!” Nami says, running up with almost as much enthusiastic delight as her captain. “It’s been ages!”

“Glad to be back,” the woman murmurs. “Torao-san was just telling me about your latest adventure.”

Luffy snakes an arm out to Robin, and she nonchalantly deflects it. Unfazed, the rubber boy clings tighter to Law and waves at Sanji. “Sanji! Robin! Sanji, this is Robin, she’s our archaeologist! Robin, this is Sanji, he’s a fish but he’s gonna be our cook!”

“I heard,” Robin says, approaching the edge of the pool. “Pleased to meet you.”

Putting aside the question of why a novice pirate crew needs an archaeologist, Sanji pushes himself out of the water to greet her. Maybe it’s simply how poised and beautiful she is, but something about this woman is dizzying. “Enchanted, I’m sure, mellorine!”

“Law contacted me for research on merfolk,” she says, the hem of her long cloak fluttering as she crouches to Sanji’s level. “I must say, it is fascinating to meet one of your kind in person. I’m afraid all my knowledge comes from books, and very old books at that.”

Sanji spares a peek at Law, who glares at him. Whatever the surgeon is fussed about, Sanji isn’t eager to find out about it. “If there’s anything you’d like to know, my dear, I -”

“Ah, you shouldn’t make such a grand offer so easily. I might well keep you here answering questions for the rest of your life.”

Robin doesn’t look like she’s joking, despite the pleasant smile on her face. Although spending the rest of his life with this lovely lady sounds like a dream come true, it makes Sanji a bit nervous.

“Sounds like Law’s gonna want to see you in his office, Sanji-kun,” Nami snickers. “That reminds me. I know we use a ton of your supplies, Torao. Here, buy Chopper something nice. Usopp, run to the village and get some food so Luffy doesn't try to eat Chopper againe, won’t you? Be a dear.”

Fishing a few pieces of treasure out of her bag, Nami tosses Law a little golden statuette, and lobs an intricately carved bowl at Usopp. Robin’s eyes track it like a shark hunting seals.

“You bet,” Usopp says with a glum salute. “See you soon.”

Law’s eyebrows shoot up, but his voice is as deadpan as ever when he responds. “Gods know you wouldn’t be able to afford my services if I actually charged you, even with this.”

“May I look at that?” Robin requests, getting to her feet in a whirl of skirts.

“I would prefer to see to my patient immediately,” Law acquiesces, passing it off to her with his eyes fixed on Sanji.

“I’m really feeling way better -” 

“Yeah, electric eel barely zapped him,” Zoro adds, the traitor.

“ _Room_ ,” Law commands. The last thing Sanji sees before landing on the surgeon’s examining table is Robin turning the statuette over and over in her elegant hands, Nami beside her gesturing out to the boat.

Law sweeps into the room seconds later, slamming his hands down on the edge of the table. “Electric eel?!”

“That really wasn’t a big deal,” Sanji mutters, levering himself into a less undignified position on the sterile sheets.

“I told you not to aggravate your injuries,” Law grumbles, already beginning to cut away the latest bandages. “You fit right in with these idiots, Sailfish-ya.”

“I keep hearing things like that,” Sanji sighs. “Make up your mind; either they’re too dangerous to be around or it’s where I belong, pick one.”

“Not everyone can keep up with their energy,” Law says, examining the edges of Sanji’s cuts. “And odd as it might seem, Luffy-ya doesn’t like just anyone so much.”

“Not like I have anywhere better to go now.” Flinching as the stark reality of that hits harder than he realized, Sanji tries to play it off as a reaction to Law’s cold hands, but the sharp-eyed surgeon isn’t the type to be so easily fooled.

“Why is that?”

Someone will tell him sooner than later even if Sanji doesn't. “I’m presumed dead,” he spits. “Perfect chance to start a new life.”

“I was meaning to ask about your family,” Law comments. It’s hardly a subtle bid for information, and the way the human doctor glances over to the stack of ancient-looking books on his desk makes Sanji wary of the motivation.

“Why is everyone so interested in my family all of a sudden,” he grumbles.

“I’ve been researching mer genetics,” Law says, reproachfully eyeing Sanji as if how the human doctor spends his free time is his fault. When Sanji doesn’t say anything, the man continues. “Specifically, I’ve found that it is not uncommon for your people to carry traits from both parents, even if you present an unrelated phenotype.”

“So?”

Law sighs, stepping away and shuffling through a pile of handwritten notes. “As your doctor -”

“I never agreed -”

“ _As your doctor_ , and you’ll be glad I _am_ if you stay mixed up with Strawhat-ya, you should tell me this kind of thing -”

“Excuse me for not thinking that my parents’ species mattered when you were doing emergency surgery,” Sanji sullenly mutters, not derailing Law’s chiding in the least.

“- because gods only know how the internal medicine might differ, and I _knew_ something was strange with how your organs are positioned, but how was I supposed to guess or take the time to examine that, given the circumstances -”

“It’s not your business,” Sanji mutters again, this time getting a glare as Law huffs another exasperated sigh.

“An injury like that could have disfigured you permanently,” Law snaps, “and without knowing more about you, there would have been nothing I could do.”

So that’s what he’s been getting at. Sanji isn’t exactly surprised, and doesn’t want to get into how _not_ disappointed he would be to lose functionality of certain organs.

“My mother is a seahorse,” Sanji says, “and _yes_ , I got more from her than my brothers did, and _yes_ , male seahorses carry young - and it’s rich, isn’t it, that she got pregnant the usual way, and the complications eventually killed her - and _no_ , there’s no way in hell _I’ll_ ever exercise that capability, _especially_ after all the shit I got for having the parts -”

“Sailfish-ya -”

“- so if something _had_ gotten ruined in there, good, I wouldn’t have to think about it -”

“Sailfish-ya!”

Oh. He went there. Well, once again, Sanji has never been much good at keeping his temper. 

Law grabs his chin, and Sanji realizes that he’s smacked his tail against the side of the table as well, making a faint smear of blood well up from his uncovered wounds. “Calm down,” Law says severely. “Don’t make it worse.”

“I’m not going to sit here and let you prod at me,” Sanji threatens, empty as it is. He doesn’t have much choice.

Sighing, the surgeon removes his hands. “At least let me take a closer look at your spine. Since a true seahorse doesn’t _have_ one, I doubt yours follows the usual conventions, not the way you bend.”

Sanji rolls onto his stomach and acquiesces to Law’s hands. “I can practically hear you thinking. Keep your nosey research to yourself.”

“It is my job,” Law grumbles.

“Just pretend you don’t know, and I won’t have to break your jaw.”

“If you decide to be intimate -”

“For fucks’ sake, Trafalgar, you’re not my _mother_ -”

“Genetically, I doubt anything could happen -”

“What did I _just say_ -”

“Just try to keep yourself safe, won’t you,” Law snaps, digging his fingers into a place along Sanji’s spine that, yeah, might have a little more space between the vertebrae than normal. “It’s hardly unusual. Every human with a uterus has to think about it -”

“That’s not what this _is_ , shitty surgeon -”

“- so I’m just _telling you_ ,” Law insists, “not to risk anything _stupid_.”

“As if there’s anyone to risk it with,” Sanji mutters, relaxing a touch. Law’s hands feel good, actually, pressing kinks out of his spine that Sanji hadn’t realized were there.

“Stranger things have happened.”

That much is fair, but if Law doesn’t shut up, Sanji really will try to strangle the human. “Where’s Chopper? Bet he wouldn’t try to tell me what to do.”

“You clearly don’t know him well,” Law drily retorts. “He took Bepo out for some air. They enjoy playing together.”

That image is both adorable and terrifying. Sanji has been told that Bepo is gentle, sure, but he’s not completely willing to rely on that information yet.

“Besides, I wasn’t talking about pregnancy,” Law adds, rolling his eyes. “As I said, that seems highly unlikely, although if you won’t let me take care of you as your doctor -”

“Then what _did_ you mean - don’t answer that - and _no_!” Sanji squawks.

“Just sex, Sailfish-ya,” the surgeon implacably continues. “The last thing I want to deal with is treating intimately transmitted diseases in an unfamiliar species, or across different species. Ordinary physical traumas are plenty of work as it is, especially given that my sources on your people are half mythology and half written in dead languages.”

“My parents did give me the Talk -” or at least Judge gave a lecture on unexpected royal offspring - “so please shut up, Torao. Besides, who the hell do you think I’ll be fucking, with my whole life upended like this?”

The human hums in a way that sounds far too pleased with himself, and finishes up with Sanji’s tail. “No one in particular. Let’s rejoin the others before someone comes looking for us, shall we?”

Luffy has once again raided Law and Chopper’s kitchen, but at least his oversized snack is keeping him occupied and out of Nami and Robin’s lovely hair, Sanji reflects, surfacing from the pool after Law transports him away. The food even keeps the rubber kid off of Law for a few seconds, long enough for the surgeon to put Zoro between them.

“I am terribly disappointed to have missed your treasure hunt,” Robin says, holding up a piece of their haul. Sanji vaguely recognizes the little golden cube, one of the more eye-catching bits of treasure they pulled up.

“Easier to look at up here,” Zoro grunts. “Unless you like being attacked in a small space while you’re relying on one of Usopp’s crazy adventures to keep you from _drowning_.”

They all pause, waiting for a retort from the inventor, before remembering that Usopp is off running Nami’s errands. A bit sheepishly, Zoro shrugs.

“These artifacts bear the language of the lost civilization of Jaya,” Robin continues, as if Zoro hadn’t spoken. “A fascinating find. Many scholars believe the city is merely a myth, and yet here we have solid proof of their culture.”

“It’s worth a lot of money, right?” Nami asks dubiously.

“Of course. More than mere gold, to the right people.”

Sanji can practically see the wealth floating through Nami’s dreamy eyes. “Perfect,” she exclaims. “Who are the right people?”

“That is the question,” Robin muses, twisting the cube in her delicate fingers as she gazes at Sanji. “A central piece of the myth of Jaya is that they earned their wealth through trade with the ancient mer civilizations. Many people chase the stories because of that.”

“We have stories like that,” Sanji tentatively offers. “Not so much about wealth, but power. Magic.”

“Not surprising,” Robin says, with a pleased smile. “Other scholars focus their efforts on the sky dragons. The artifacts of power that they bestowed, upon both Jaya and the merfolk.”

“What kind of power?” Nami asks.

“Everyone believes different stories,” Robin shrugs. “For most, they think it is whatever power they most want, and there are so many myths and rumors, no one can prove anything. But perhaps the merfolk have different stories.”

Sanji hesitates. Judge is obsessed with the glories of the past; much of the misery Sanji experienced as a child goes back to that. “Probably the same stuff,” he finally says. It all leads back to violence, although there are a few myths Sanji dreamed of, in secret.

“Boring,” Luffy complains.

“Yeah, we only care about the money,” Nami laughs.

“I suspect that what Robin-ya was getting at, is that you should take care not to sell records of such power into just any hands,” Law interrupts. 

“Wait, isn’t it - If that city was lost, how can you read their records?” Sanji asks. “Would anyone else even be able to?”

“How indeed,” Robin murmurs. “A gift of my people, shall we say, Sailfish-san? I come from a very scholarly family. But few even among them could have read this.”

She holds up the little cube, the artificial light in the cave gleaming off of its carved sides. In her hands, it nearly seems to glow with a light of its own, a pale shine not unlike the excited light in Robin’s eyes.

“A poneglyph,” she concludes, grinning widely. “The most precious of ancient records, and you fished one out of a simple shipwreck. This could lead you to treasure far greater than any common gold.”

“How?” Nami asks. “And - I mean, we know you, Robin, you don’t just mean that the historical knowledge is invaluable, do you, because that’s great and all, but we’ve got a ship to pay off.” 

Her gaze goes positively dreamy for a moment, but Robin shakes her head. “While that is undeniably true, no, I believe there is physical treasure to be found. Let me show you.”

Touching a few spots on the cube, Robin purses her lips in concentration. “You know, the friendship between merfolk and ancient human cultures is no myth. There is plenty of archaeological evidence. In fact, given some of the inscriptions here, I suspect I know where this will lead - ahah!”

Robin holds out her hand and the cube floats above it, the carved inscriptions glowing a deep, rusty orange. A tangle of shining lines spread above it, and Robin grins, her expression eerie in the magical light. From this angle, the image is difficult to make out, but -

“It’s a sea map,” Sanji blurts. Much more familiar to him than the surface maps the humans use, and unless he’s mistaken, the area it depicts is familiar too.

“More evidence of collaboration,” Robin murmurs.

“Is it a magic treasure map?!” Luffy asks. “That’s so cool!”

One point on the map glows brighter, a cool blue in the threads of gold. By Sanji’s reckoning the spot is just below sea level, along the coast of an island not far from here.

“I do believe it is, Luffy-san,” Robin agrees.

Nami fearlessly waves her hand through the map. The lines waver, and reform like swirls of ink. “I recognize this coastline.”

Sanji recognizes the trench, a deep slice through the ocean floor that very nearly touches the spot marked on the map. “South of here.”

“What’s south of here?” Usopp pants, stumbling into the cave with his arms full of bags. Chopper trots in behind him, similarly laden, with Bepo sniffing at a few of the bags in particular.

“Our next adventure!” Luffy cheers, bounding over to them. “Guess what, Chopper, we found sunken treasure, and none of it was a cool statue, but some of it is a pony map!”

"Poneglyph," Robin murmurs.

“I definitely want more treasure,” Nami sighs, “but are you sure, Luffy? Who knows what this leads to.”

“Sure,” the rubber kid blinks, abruptly sobering and turning to Sanji. “If it’s fish-people treasure, maybe Sanji will like it! It could be really cool!”

“I won’t get my hopes up,” Sanji mutters.

“Shishishi! That’s dumb. We’re gonna have tons of fun, so Sanji can forget the bad stuff. I already promised! So, Sanji, what kind of treasure do you want?”

When he was little, Sanji wanted to become invisible. One of his favorite stories featured a princess with a magical crown, who could sneak away when her kingdom was in trouble and save the day. Barring that, he coveted the legends of merfolk who could transform; being invisible would make him safe from his brothers anywhere, but if he could flee onto land, then at least that would be a temporary escape.

“Fire that can burn underwater,” he deadpans. “Would make cooking way easier.”

That makes Luffy’s attention snap back to Usopp, who is laying packages wrapped in butcher paper out on the stone floor. “Torao! We need barbecue!”

The surgeon sighs, fending off Luffy with one hand while he gestures with the other. “Room.”

They’ve clearly done this before. Suddenly Bepo is nowhere to be seen, and in his place is a jumbled mess of equipment. Usopp sorts out the pile of camping grills, Zoro moves the coal into haphazard but serviceable beds, and Chopper rushes around rescuing little jars of seasonings before they can be trampled in the rush. 

Nami drags some of the meat over to Sanji. “Want to do your thing, Sanji-kun?”

“I would love to, Nami-swan~!”

Everyone has an opinion about the preparation, and Sanji ignores them all in equal measure. No, he will not use any of Usopp’s special spicy sauce; no, he will not let Luffy taste the meat raw; no, he will not add cotton candy to the seasonings. He would be happy to cater to Nami and Robin’s preferences, but they merely shake their heads and say they trust his judgement. 

“It seems food is the heart of any culture,” Robin muses. “You realized that right away, didn’t you, Swordfish-san?”

“Sharing a meal..." Sanji says. “Well, that’s as simple as it gets, right? That sense of camaraderie.”

She hums in agreement. “It is difficult not to love Luffy, after eating with him. There is simply no faking that kind of joy.”

Wincing at the memory of the first time he saw Luffy eat, Sanji still can’t disagree. Even then, he knew the kid wasn’t a bad person. Just an exceptionally strange one.

It feels good to cook properly, even if this seaside barbecue is barely more sophisticated than campfire cuisine. Law and Chopper have every ingredient Sanji asks for, and Chopper is eager to help while Zoro keeps Luffy at bay. By the time the first meats are done, Sanji feels settled in his skin, and tentatively hopeful about this start of a new life. 

Despite how much food Usopp and Chopper lugged back, it doesn’t last very long. In what feels like the blink of an eye, Nami is marshalling her troops to clean up, and Sanji’s head is spinning from the endless compliments. He’s sure he’s blushing, unable to keep a silly grin off his face. He’s never had the chance to cook for people this way. If they’re always so enthusiastic, Sanji can imagine being happy to cook for them every day.

“I wanna sleep with Bepo!” Luffy yells, throwing down a broom after sweeping the cooling coals out of the way.

“Me too!” Chopper cries, chasing Luffy deeper into the cave. Usopp is long gone, carrying dishes back to the kitchen, and Sanji can’t even remember seeing Robin move, let alone leave for the night, but she’s undeniably missing as well.

“What about you, Sanji-kun?” Nami asks, passing him one last grill plate to scrub with sand. “Law has plenty of room for us, but do you want to stay out here?”

“The tank is still set up,” Law volunteers.

Sanji swishes his tail through the dark water, and thinks about it. The tank was nice and warm, and this inlet is dark, and likely to be pretty creepy once everyone is gone. “Tank.”

“Why don’t you help Swordfish-ya, Zoro-ya,” Law says, voice rapidly fading as he escorts Nami out.

Looking up from his own pile of dead coals, Zoro scowls at the surgeon’s vanishing back. “As if he couldn’t just whoosh you there,” he grumbles.

There’s no bite to it. Brushing his hands on his pants, Zoro comes over to Sanji, and offers a hand to help him get farther out of the water before picking him up.

“Sorry to soak you again,” Sanji says, just to break the sudden silence with more than the sound of dripping water.

“Used to it.”

Silence again. Zoro adjusts his grip, sliding one hand up Sanji’s tail. Sanji tries to decide whether _freaking out_ after dealing with Law’s weird shit is justified. Probably not. The swordsman carried him all around the Baratie just like this only hours ago.

“Least I can do,” the human adds.

They’re still just standing in the cave. Should Sanji take his arms off Zoro’s shoulders? Would that be weirder? It’s too close, somehow, but the damn marimo might _notice_ that it’s weird if Sanji moves, so -

“There’s salt in your eyebrows,” he blurts instead.

“What?”

“Don’t you _bathe_ , marimo? Humans aren’t supposed to get crusty like a tidal zone.”

“We’ve been - when would I have had time for that?!”

Scoffing, Sanji scrubs a finger against the grain of Zoro’s eyebrow. Salt flakes off, dusting the swordsman’s functional eye, and he blinks furiously.

Their faces are very close. Zoro’s eye is grey like the stormclouds Sanji sneaks up to the surface to watch, and in the chill of the cave, his dry human skin is comfortingly warm. 

Zoro hefts him a little, carefully drawing his hand down the folded spines of Sanji’s dorsal fin. “Anyway, you’re one to talk about salt, fish-cook.”

Rolling his eyes as much to break eye contact as to convey his disdain, Sanji whaps Zoro’s leg with his tail. “Besides the point. C’mon, algae-brains, I want to sleep.”

“I should let you drag yourself there,” Zoro retorts, as he walks.

“And set back my recovery again? Law would skin you.”

The swordsman shudders, muscles moving against Sanji. “He really might.”

The tank looks exactly how Sanji left it. Big and empty, with the machinery whirring quietly on the floor. Still, it’s not so bad. Zoro even holds Sanji’s arms to brace him up as he eases his tail in, instead of tossing him into the water the way the swordsman usually might.

“Are you okay with this?” Sanji asks, hands still gripping Zoro’s forearms. He understands Zoro’s desire to protect Luffy, and Sanji only brings trouble to those dear to him.

“Told you, Luffy makes the decisions. The important ones,” Zoro amends, without pulling his arms back. “After this morning… well, captain’s not the only one who wants a piece of your family, if they come looking for you.”

It’s hard to clear his throat to speak, and harder for Sanji to meet Zoro’s eyes. “They’re dangerous.”

“So’m I,” Zoro grumbles. “So’s Luffy. Even the witch and Usopp can handle themselves, an’ you’ve never seen anyone like Robin. Don’t be a coward, cook.”

More than dangerous, they’re stubborn; Sanji’s family and these pirates both. Sanji doesn’t deserve the humans’ support, but it’s clear he can’t give it back. Sinking into the warm water, Sanji trails his fingers down Zoro’s tanned arms until the very last moment. And then flips him off.

Zoro makes an outraged sound, muffled by the water between them, and leans down beside the tank to return the gesture. Sanji grins, turns a tight somersault, and flicks his tail out of the water to splash the man.

Sanji watches Zoro say something else, still too low to hear, and only surfaces when the swordsman stomps to the door. He breaks the surface of the tank just in time to hear a quiet _goodnight, fish-cook_ as Zoro vanishes from sight.


	7. Chapter 7

Robin accompanies them when they leave Law’s cave the next morning. Still wrapped in her dark cloak, so much so that looking at her is like trying to see into shadows, even in the bright sunlight out on the ocean. Sanji tries not to think about it, avoiding eye contact with any of the humans as they leave the shelter of the coastline.

He’s feeling awkward around the marimo this morning, shaken by the combination of Law’s insinuations and Zoro’s uncharacteristically gentle behavior the night before. Robin obviously noticed right away, her sharp eyes tracking between the two of them at breakfast, and Sanji just knows that Nami will figure him out in seconds if her attention lands on him. Luckily she’s preoccupied with the poneglyph map, but who knows how long that will last once they’re set on their course.

So he can’t look at the ladies, can’t look at the swordsman, can’t risk letting Usopp or Luffy draw him into a conversation that would attract the others. Sanji isn’t sure if he would rather throw Zoro overboard, or… 

Well, nothing he’s willing to think about, that’s for sure. He’s feeling much more comfortable around these people, but getting _that_ familiar is something else entirely.

Their destination isn’t far, and that’s definitely for the best, and not only because Sanji can’t wait to be free of his tiny transport tank. Adding Robin to the crew pushes the little boat to capacity - it’s no wonder the humans are working so hard to get a proper ship. Nami wants to drop off some of the treasure with their shipwright before they go haring off on another adventure, so that’s the first stop of the day.

“We’re not sailing into a shipyard, are we?” Sanji asks, breaking his silence as they sail along the coast of the island. Stopping at the Baratie was one thing; getting so close to a whole human city, on _land_ , is another entirely.

“Not exactly,” Nami says. “Don’t worry, Sanji.”

“Franky’s cool,” Usopp adds.

This is not exactly reassuring, but Sanji takes them at their word anyway. He can always jump overboard to get away if it looks too risky. After another round of Law and Chopper’s attention, he’s feeling nearly as good as new, even if there’s a noticeable crater of tender, healing scales left on the side of his tail. Only the deepest parts of the wound still need bandaging.

“Franky’s set up outside the city,” Zoro says, looking irritated when Sanji just gives him a jerky nod.

Submerging himself up to his eyes in the tank, Sanji pointedly looks anywhere but at the swordsman, and goes back to watching the coastline flow past. He can’t help feeling nervous whenever they pass other boats, all small fishing outfits by the looks of them, but still too close for Sanji’s comfort. It only gets worse as they approach the city, more and more sea traffic making him bite his lip and clench his fingers into the edge of the tank until they hurt.

Noise travels easily over open water, the conversations from other boats and general commotion ringing in his ears until Sanji gives up and retreats under the water completely. He has to trust Luffy and the others. It would be far too easy to get tangled up in another human’s net if he jumped ship now.

Usopp comes for him a while later, knocking softly on the side of the tank until Sanji resurfaces. “We’re almost there.”

“Thanks,” Sanji mutters, a little embarrassed that he needed to hide. The boats have thinned out, the human buildings along the coast smaller and farther apart as they pass the far edge of the city. Eventually, Nami steers their boat in closer to shore, heading for a single pier sticking out into the ocean.

Sanji is no expert on seaports, shipyards, or anything of the sort, but this does not look like what he imagined. There are bits of ships pulled up dry on the shore, piles of material that look liable to collapse any minute, and the strangest human structure Sanji has seen right in the middle of it. Somewhere in the mess, a loud crash and destructive clamour rise over the scene.

“Franky!” Luffy howls, slinging himself off the mast into the distance, quickly disappearing behind half of a ship’s hull, left high and dry like a beached whale.

A cacophony of voices greets him, clamouring through the junkyard. Sanji’s tail thrashes through the water in his tank as the others disembark, tying the boat up at the end of the pier.

“Can I wait in the ocean?” he asks, eyeing the direction Luffy disappeared. This is… an awfully exposed and honestly humiliating way to meet new people. 

“Whatever,” Nami shrugs, double-checking that everything is secure. “Zoro, give Sanji a hand -”

Sanji doesn’t need the marimo’s help for this, and can’t stand the idea of letting the swordsman pick him up today. When they left Law’s, he managed to get the surgeon to transport him using his devil fruit instead. Sanji isn’t sure what he’ll do if Zoro gets him that close.

“I got it,” he chirps, gracelessly flipping himself out of the tank and into the ocean before Zoro can cross the little boat to reach him. The water is brisk and refreshing after the tank, blessedly quiet but for the surf pounding into the nearby shore. A school of fish flash silver in the sunlight as they scatter, rushing for cover in the shadow of the pier.

Sanji gets a few raised eyebrows as the surfaces, but no one comments on his hasty exit. Robin merely smiles at him, picking her way over the puddle his splashing made to keep her cloak dry as she steps out of the boat, and Sanji fights down a blush. Somehow it feels like she knows everything about him.

“I’ll ask Franky to come get the treasure, and introduce you,” Nami tells him, shooing Usopp and Zoro down the pier. “Bet he’ll have a ton of questions.”

About what, Sanji doesn’t get to ask. These humans are always in a hurry, and now is no different. It’s a relief for Sanji, who is happier for a moment to himself than he expected. Being stuck in a tank underground isn’t relaxing at all, and neither is sitting around in the tank on the boat, no matter how thoughtful it is of the humans to accommodate him.

The pier reaches far enough for large ships to dock, pilings stretching deep down to the ocean floor. It’s a natural haven for small fish, attracted by the shelter, and predators drawn by the plentitude of prey. Touching the barnacle-encrusted piling for an anchor, Sanji watches a barracuda slice past the pier, and enjoys the feeling of fresh water over his skin.

A curious angelfish nips at his fingers, and Sanji stays still, letting the commotion his arrival caused be forgotten. The angelfish, beautiful in shades of green and purple, eventually loses interest, swimming off to investigate the other side of the piling. Slowly sinking to the ocean floor, Sanji rests on the white sand as shoals of fish billow around him.

“You don’t have to worry about humans,” Sanji mutters, propping his head on his elbows in the sand. “Well. You do. But not about _feelings_ for humans.”

The fish don’t answer, utterly ignorant of Sanji’s woes. They flash and scatter, fleeing the languid approach of a small shark, and Sanji rolls onto his side, mended sailfin spread flat on the soft sand as he stares up at the surface.

He used to do a lot of this, find a quiet patch of shallow sea and simply wonder what else might be out there. The Baratie and Zeff gave him some hope that humans might not be all bad, even if he never dared to meet the other cooks, but Sanji never imagined wanting to… to see where something like this might go, whatever the tension between himself and Zoro might be.

“I’ll find out eventually, if I really stay with them,” Sanji tells the uninterested fish. The idea still tastes strange on his tongue, sweet despite the ocean salt. Staring up at the pier, the sharp shadow and refracting beams of sunlight, he sees a disturbance near the surface, fish darting for safety as something moves above the water.

Sanji swims up, hand trailing along the soft corals and barnacles encrusting the piling, and finds the humans peering over the edge of the pier at him.

“There you are,” Zoro mutters, straightening abruptly and turning away.

Ignoring the marimo’s weird behavior, Sanji takes in the unfamiliar figure looming over the others. Tall, sure, but his shoulders and arms are _massive_ , and look like they’re made out of… metal? Sanji doesn’t know where to start with this guy, between his outrageous hairstyle and lack of clothes; Sanji is pretty sure most humans wear _something_ on their legs, but...

“You really are a merman,” the big guy blurts, and Sanji is almost pleased enough that he got his gender correct that he disregards the incredulity. Almost.

“What are _you_?” He retorts. This is the least human-looking human Sanji has ever seen.

“Don’t you wanna know,” the guy says, sounding pleased. “Can’t go giving up all my SUPER secrets right away! Buy a guy a drink first, fish-bro!”

“Oh my god,” Nami sighs. “Sanji, this is Franky, and _please_ don’t ask him about his so-called upgrades, we’ll be here all day.”

“Then let’s see this treasure, sis, and I’ll get back to work,” Franky promises. Beside him, Luffy looks disappointed that the weirdo’s… weirdness… won’t be the topic of conversation. “I’ve already got my guys started on the bones of your ship; I know you lot are good for it!”

Nami hauls a bag of gold out of their boat, and Franky whistles. “You won’t charge us a conversion fee or anything, will you?” She asks, batting her eyes at him.

“You know those eyes don’t work on me, girlie,” Franky mutters, hefting a piece of the treasure. “But nah, pawning this off will be no problem. Unusual stuff, I bet I’ll get even more for it than raw gold. I’ll be able to get the best materials out there for your ship!”

“Yahoo!” Luffy shouts, hanging off one of Franky’s arms. “When will it be done, huh?”

“You can’t rush art, Strawhat-bro,” Franky snickers. “Besides, sounds like we’ve got some adjustments to make for fish-bro here, right?”

“Is this what you usually do?” Sanji asks. He can’t help feeling skeptical. Building a ship seems complicated, and he doesn’t see how the piles of junk all around will become one.

“I’m more of a demolition guy, by trade,” Franky mutters, “but I’m gonna build a SUPER ship, the best one anyone’s seen since the Pirate King.”

“OUR ship!” Luffy yells. “And it has to fit Sanji!”

“What kind of adjustments are we looking at?” Nami asks. “Will it cost more?”

“A ship that’ll accommodate a merman,” Franky muses, a sharp look in his eyes that tells Sanji that despite all the weirdness, this guy knows what he’s doing. “Well, it’ll be a challenge, sis, but with this kind of gold and a little time, I’ll finagle something that’ll knock your socks off!”

“Sanji’s our cook!” Luffy chimes in. “So he has to have a kitchen!”

Franky’s eyebrows shoot up, but he doesn’t question Luffy’s statement. “Oh yeah? Then I’ll have to pay special attention to the galley specs, huh? You’re lucky I’m such a SUPER shipwright, ‘cause this’ll be the feat of a lifetime.”

“I’ve got some ideas,” Usopp pipes up, “y’see, ‘cause we’ve had to put this tank in for Sanji, and Zoro has to carry him around on land, which is a pain, no offense Sanji, but it doesn’t make sense to have to do that all the time on our ship, once you’ve built it, and -”

Clapping Usopp on the shoulder hard enough to nearly knock him into the water, Franky grins maniacally. “Yo, come sit down with me in my workshop, lil’ bro,” he suggests. “Between the two of us, we’ll get this figured out in no time!”

“I don’t mind carrying him,” Zoro says under his breath. Sanji barely hears him over the splashing waves, but it makes his cheeks burn all the same. Whether or not the swordsman minds it, Sanji is sick of needing help to get everywhere. 

“What a good bro,” Franky says, tearing up.

“Yes, yes, it’s been very touching,” Nami says, “but I don’t want these two dripping all over our new ship, so I expect great things from you, Franky.”

“And me!” Usopp pouts. 

“I was already planning for an aquarium,” Franky says with a wink. “I’ll just make it classy for you, fish-bro.”

Sanji is wary of what this guy might consider classy, but the other humans clearly trust his design aesthetic. Not that their taste is reassuring, but what choice does he have?

“And you,” Nami sighs. “You’re gonna stay here then, Usopp?”

“You know, I have this syndrome, if I have to follow ancient magical treasure maps I’ll start to lose -”

“I get it,” she interrupts. “We’ll pick you up on the way back, shouldn't be more than a day or two.”

“Unless something truly terrible happens,” Robin muses. “Why, we could all be eaten by a sea monster, or a sudden tsunami might wash away Franky’s workshop…”

“Do you think we’ll find a sea monster?” Luffy demands. “Sanji, if we fight a sea monster, will you cook it for me?”

“Don’t even say that, sis,” Franky shudders. 

“Let’s just get this over with,” Zoro grumbles. “If we see a sea monster I’ll slice it in half before it can so much as look at us, so there’s nothing to worry about.”

“Except freak storms,” Robin adds. “Lightning strikes. Strange magic, or unknown phenomena; who knows what we might find at the end of this search, surely something fantastic if the ancient civilizations that made the poneglyphs created this map.”

She sounds altogether too excited about all that. Sanji remains in awe of her beauty and knowledge, but Robin is a terrifying human even by his recent standards.

“We’ll have a SUPER new plan when you get back!” Franky promises.

“Because none of that is going to happen,” Usopp nervously adds. “Right, guys? Guys?”

“Who knows,” Robin says, covering her smile with one graceful hand. Luffy has clearly zoned out of the conversation, and Nami just sighs, beginning to get the boat untied.

“Can you get back in the boat by yourself?” Zoro asks.

“Watch this,” Sanji retorts, flipping him off as he dives. He’ll need some space to pull this off, but the damn marimo will have to eat those words.

With a few powerful strokes of his tail, Sanji cuts through the water, making the most of his innate speed as he zooms toward the surface. Breaking through with enough force to propel himself over the side of the boat is easy - Sanji has made jumps far higher than this. Landing in the small tank is trickier, and he has to hide a wince as he slams his shoulder into the side, but it’s worth it to see the dumb expressions on the humans’ faces.

“SUPER cool, fish-bro!” Franky exclaims, giving him a big thumbs-up.

“Gonna bust your damn tail again, doing shit like that,” Zoro mutters, wiping salt water off his face. He was standing closest to the boat, and Sanji does not feel even a little bit bad about it. Seeing the marimo all grumpy and uncomfortable is far too satisfying.

A pod of dolphins follows them out, leaping and playing in the boat’s wake. Sanji is a bit jealous. Maybe he can swim back on the return journey, instead of lazing around in his tank.

“How did you find Franky?” Sanji asks, once the hubbub of leaving is over and the humans’ little boat is smoothly sailing out onto the open sea.

“His foster brother started Water Seven,” Nami says. “Best shipbuilders in the area. The two of them were raised by a great shipwright, but they had a falling out, so Franky doesn’t work with Iceberg anymore. Still has all the skills, though.”

“Plus he’s way cheaper,” Zoro adds. Nami glares at him.

“Given how much money we usually _don’t_ have, that’s important!” She snaps. “Cheaper, and way less conspicuous. Plus, he’s even more of a creative genius than Iceberg, and that’s gotten even more important now that we have Sanji to think about.”

“Franky is a very passionate artist,” Robin says, picking her way across the boat to sit beside Sanji’s tank. Up at the top of the mast, Luffy swings around like a monkey, grabbing at seabirds.

“I got that impression,” Sanji acknowledges. “Although to hear it from someone like yourself, it’s high praise indeed!”

Robin laughs, and Zoro scowls over his shoulder at them. “Praise well deserved. Besides doing good work, Franky has been very understanding. We all want to avoid the eyes of the Doflamingo Family, so it has been perfect to have someone willing to plan such a large project outside of the usual channels.”

“Who are they?” Sanji asks. It’s an old name, and he’s heard Zeff’s cooks complain about the regulations imposed by the Doflamingo Family in this part of the ocean, but Sanji doesn’t know enough about human history or politics to understand more.

“The reason Law won’t leave that dreary cave, for one,” Nami mutters. Above them, Luffy has gone still, glowering into the distance.

“Let’s just say it’s wiser not to garner their attention,” Robin concludes. “But it’s nothing for you to worry about, Sailfish-san.”

“When Franky finishes our ship, we’ll be out of here for good!” Nami adds. “You’ll see, Sanji, soon none of us will have to think about the Doflamingo Family, or _your_ family, ever again.”

~o~O~o~

As they sail, the weather worsens, clear skies giving way to blustering winds and dark clouds skating by overhead. By midday, the air is nearly as wet as the water, thin sleet and dense fog alternating as they approach the island on the map. Sanji can barely make out the back of the boat, aside from the eerie glow of the poneglyph as Nami and Robin pore over it.

“You’re sure we’re going the right way?” Zoro asks. “All this shit looks the same.”

“Shut up,” Nami mutters. Her face is barely visible from Sanji’s tank, illuminated in strange relief by the glowing map. “Of course I’m sure. And I don’t want to hear that from you, of all people.”

As they bicker, Robin comes over to sit by Sanji again, a fond smile on her lips. “Never a dull moment, is there?”

Sanji shakes his head, rather enjoying the low rumbles of Zoro’s voice. When the swordsman isn’t getting up in Sanji’s face, his grumbling is almost endearing.

“Nami told me about your family,” Robin begins, eyeing Sanji like she can see straight through him. “I hope you don’t mind, Sailfish-san.”

“It’s not exactly a secret,” Sanji says. As much as he would like to forget about them, it’s not that easy.

“I won’t force you to talk about them, but if you are willing, I would like to hear more about your mythology, what your people believe about the historical relations between humans and merfolk. Whether that history influences your lives. It sounds as though you may have some knowledge of this.”

“It’s not so much the stuff about getting along with humans,” Sanji tells her. “My fa - Judge, he doesn’t care about humans, but the other old stories, he’s very invested in those.”

“Oh?”

Staring at the thick fabric of Robin’s cloak instead of her piercing eyes, Sanji shrugs. “Like we talked about, power. Glory. Judge wants to create the greatest mer civilization of all time. He thinks some of the stories hold the key to his goal.”

“How so?”

“He tried to recreate mer to human transformation,” Sanji sighs. “It didn’t work, but his experiments… my brothers are much stronger than most mers. They all take after him, but my mother was afraid of what might happen, and tried to nullify some of the magic. She died, and I’m… normal.”

“Far from normal,” Robin says, ducking her head to catch his eyes. “I can see that much already. Have those experiments continued?”

“No,” Sanji says, feeling the same relief he always does at the fact. “He’s interested in augmentation instead, in creating more soldiers like my brothers. But it’s…”

Hesitating, Sanji wonders if he should admit this. Sheltering one merman is all well and good, when there is no greater threat than, perhaps, a vengeful family. But Judge always wants more.

“It’s crazy,” Sanji prefaces, looking away again. “But he wants to take over on land, too. That’s why he was researching the ancient mythology stuff, because if humans and merfolk could coexist on land and in the water, why couldn’t merfolk take over the islands too?”

“A man of great ambition,” Robin says, not looking particularly concerned.

“The experiments failed,” Sanji says, feeling like he’s admitting a shameful fear, “but Judge isn’t too proud to do things piece by piece. I worry that he’ll try something worse, that even among humans I’ll never be out of his reach.”

It’s all too fresh in his mind, Judge’s terrible moods and Sanji’s brothers’ abuse. As fantastic as it has been, to find this ancient treasure and hear Robin’s excitement, to see magic no one has used for centuries, it makes Judge’s goals more real, too.

“He believes you to be dead,” Robin points out. “Worrying overmuch will only make you feel worse.”

“For now he thinks that,” Sanji mutters. “Do you think -”

“The shitty fish is worrying himself to death again?” Zoro demands, hauling a rope in their direction. Whatever boat business he’s up to, Sanji can only guess, but the timing is atrocious.

“No!” He snaps.

“Your face is gonna get stuck like that,” Zoro says, “and you’re already weird-looking, don’t make it worse.”

“ _You’re_ weird-looking!”

“You’re gonna stress yourself into an early grave,” the marimo retorts, “and then Luffy will eat you, I mean it, if you die here -”

“What the fuck, you bastard, why would you _say_ that, and in front of Robin -”

“It seems likely,” she muses, and Sanji blanches.

“Too soon,” he grumbles. It’s like their soft moment in the darkness of Law’s cave never happened, that strange warmth leached away by this clinging fog. Why did Sanji ever think he likes this idiot, again? “You’re animals, the lot of you, all humans are awful.”

“Dunno about animals, coming from a guy that’s half _fish_ -”

“I suppose we still don’t know for sure if eating a merperson makes one immortal,” Robin muses. “Perhaps we should kill Luffy to find out.”

“You want to _what_?!” Zoro balks.

“Who even told you about that, it was horrible, Robin, my flower, I’m _sure_ that’s all nonsense -”

“No one is killing anyone, or dying, that was my whole point, you both need to lighten up -”

“Shut up!” Nami orders. “We’re almost there. All hands on deck!”

The little boat is _entirely_ deck, but the point still stands. Everyone gets back to work, and soon, the island comes into view.

They skirt in toward the coast, all forbidding rock, dark and damp in the sea-spray and fog. Everything feels disconnected, the coastline disappearing a bare handful of boat-lengths to either side, sight and sound both drowned out in the sea of grey.

Following the map, with Nami’s expert touch maneuvering the boat around spurs of rock and the suspicious wave patterns that mark obstacles just beneath the surface, they eventually come within sight of a cave. It’s not much to look at, just a rough hole in the side of the low cliffs, but the poneglyph map clearly points into it.

Sailing in close, Nami eyes the opening. “That’s not enough headspace for the mast.”

They can only sail this close to shore because the ocean trench Sanji recognized on the poneglyph nearly touches the island at its end. The humans’ boat has a shallow draft, but it still isn’t built to sail right up to the coast on an island like this, where the ocean floor is all sharp rock instead of tropical sands.

“Looks close enough to me,” Zoro says.

“Right now, there is a _huge_ difference between actually enough, and _close enough_ ,” Nami corrects, glaring him down. “And it’s whether we’ll still have a mast to sail back with.”

“Nami, are you suuuuure,” Luffy whines, perched out on the prow of the boat, as close as he can get to the cave. “Maybe it’s actually close enough, and we’re just not close enough to see.”

“This is ridiculous,” Nami mutters. 

“Perhaps at low tide?” Robin says. “Of course, then he dangers of running aground as we approach the shore are much greater, too.”

“I’ll go check it out,” Sanji offers. “No point waiting for the tide.”

“Should be low in an hour or two,” Nami sighs, eyeing the overcast sky. “We’ll be able to maneuver the boat in, then.”

“I’ll be right back,” Sanji promises.

Zoro looks like he wants to say something about it, but Luffy excitedly waves Sanji off, and the swordsman keeps his sullen mouth closed.

“Come get us if it’s exciting!” Luffy demands.

“Come get us if there’s treasure,” Nami says.

“If there are any ancient relics, and if nothing untoward happens to you in the darkness -”

Sanji is becoming fond of the humans. He really is, but they’re a bunch of single-minded children. No matter what he finds in the cave, he’ll be back soon to tell them; they can wait patiently until then. Diving out of his tank, Sanji lets the rush of the ocean swallow up their words, and swims down to orient himself. The choppy weather has made it impossible to see what they’re sailing above.

It’s a lot to take in. This close to the shore, the deep ocean trench rises, the bottom cluttered with shipwrecks pulled into its depths by the tides. Even with a natural explanation, it still seems like an awful lot of ships, a veritable forest of disintegrating wood as Sanji sneaks between the ruined hulls. This is the smarter way to go, instead of crossing the shallow water to the coast with no more cover than loose rock.

Who knows what that map might lead them to - he’s never explored around this island before, and he’s not going to rush in headlong. If nothing else, the eerie graveyard of ships provides plenty of places to hide as Sanji approaches the cave entrance at the shore. 

Between the bits of wreckage, Sanji can see familiar disturbances in the sediment at the bottom of the trench, and steers well clear of them. Giant bobbit worms leave markings like that when they burrow into the silt, and he has the experience to know better than to disturb their trap. Some of the smaller shipwrecks have suspiciously fresh breakage, ragged rents in their hulls like something has snapped right through them.

As Sanji watches, a much less prepared fish swims too close to one of the smaller hidden burrows, and a worm longer than Sanji’s tail lunges out, pincer-like jaws cleaving the fish nearly in half before dragging it back into hiding. The whole thing is over in barely a second, leaving only a puff of disturbed sediment and a thread of blood floating in the water.

Sanji leaves the scene as quickly and unobtrusively as he can, before the taste of blood in the water can draw the attention of any nearby predators. He sticks to the shipwrecks where he can, avoiding passing above any more of the worm burrows, and swims up toward the end of the trench.

To Sanji’s surprise, the trench doesn’t vanish into the seafloor offshore. Instead, it continues all the way to the coast, lining up perfectly with the entrance to the cave. As he swims between the bits of ruined ships, Sanji can see that the natural conclusion of the trench has been extended, dug into the bedrock to allow easier access to the cave.

It’s like nothing Sanji has ever seen before. His people don’t build this way, don’t have the capability to remove solid stone at this scale. And yet, he can’t imagine why humans would have done it, either.

Everything changes at the mouth of the cave, the wreckage prevented from drifting into the channel by the remains of ancient masonry. Swimming to the bottom and examining it, Sanji can only conclude that the time-ravaged wall is also human-made, even though he can’t imagine how humans would build a wall underwater. Despite its obvious age, the structure has held up to the tides and everything else well enough to keep the tunnel beyond clear of debris.

A small boat could still clear the top of the barrier, if not by much, once the tide goes down enough to allow that boat space to sail into the cave. It’s a very precise job, for what seems to be an entirely unremarkable sea cave.

Sanji is no fool. Proceeding into the dark tunnel, he goes even more cautiously than he did to avoid the bobbit worms outside. There are some of those here too, but Sanji can’t help suspecting that there must be something more to be wary of as he swims into the gloom.

Like Law’s cave, the tunnel is cold as Sanji swims down it, deeper and deeper beneath the island, but this one goes much farther than the surgeon’s home. Sanji has to slow, using the feeling of the water shifting around him and splashing off the walls of the tunnel to guide him as the darkness becomes complete. From the sound when he puts his head above water, the tunnel ceiling is still not far above, certainly not yet high enough to allow a boat through.

Finally, the tunnel curves, and Sanji can see a glimmer of light ahead. He goes still, trying to hear if anything is there, but nothing is audible through the lapping echoes of the water’s natural movement. Beneath the waves is the same, silent and no hint of movement beyond the faint current.

The light is beneath the water. As Sanji gets closer, he can see that the tunnel walls are carved, reliefs wearing smooth under the constant brush of waves. Here and there amongst the patterns, glowing crystals shine, illuminating images of people between the ornate decorative motifs.

Humans and mers both, sometimes even together. Several of the scenes bear geometric patterns like the Jayan treasure Sanji brought the humans to find, but far more are unfamiliar. He’s so focused on the carvings, on the otherness of the light as it flows along the smoothed shapes, that the next time Sanji lifts his head above the water, he’s shocked to hear a noise.

Diving back underwater with a clumsy splash, Sanji presses himself up against the wall and winces. Maybe whatever is here won’t notice, but his luck is never that good. Eyes darting around, he confirms that nothing else is moving nearby, and sneaks back to the surface.

It’s music. Human music - Sanji isn’t well-versed in human instruments, but there are some sounds that simply can’t work underwater, and he thinks he’s heard something like this back at the old geezer’s restaurant. Sometimes the other chefs would play and sing at night, not well according to Zeff, but Sanji has always been enchanted by the unfamiliar sounds.

The tunnel weaves deeper underground, and the crystals appear closer together, until their light breaks through the surface of the water nearly as bright as day. A wide chamber opens ahead of Sanji, and the music rings throughout the cavernous space, bouncing between the high ceiling and the surface of the water.

The center of the space is deep and dark, the light from the crystals unable to penetrate far into the gloom, so Sanji sticks to the edge as he swims.

Nothing else moves. There should be _something_ , invertebrates or small fish feeding off the algae growing near the crystals at the very least, but the cold water is still, the faint rhythm of the ocean outside dissipated almost entirely by the distance.

Along the edge of the cavern, there are narrow alcoves carved out of the rock, both above and below the water. Sanji pokes his head into the shadowed entrance of one of these, wide enough to swim into but far too narrow to turn easily in, and finds a sculpted figure lying in repose. It’s human, a woman with clasped hands holding a sword over her chest.

Feeling a chill run down his spine, Sanji backs out of the alcove and swims to another one, deep enough that it would never be exposed by the tide. A mer, likewise depicted lying as if asleep, a coral crown over his heavily styled hair.

This is a tomb. All the alcoves are the same - or all unique, each figure accompanied by carvings in the walls of events from their life, centuries of history in endless rows. Every sculpture rests on a slab in their chamber, raised enough to show the cracks revealing that these cover something more, are not simply remembrances. Sanji darts from one to the next, increasingly torn between wonder and unease as the music swells in the silence of the catacomb.

The far end of the chamber is too distant to see clearly, so Sanji steels himself and heads in that direction. As he does, the water drains out of the cavern with the ebbing tide, beginning to leave the row of alcoves at the waterline uncovered. From the markings on the stone, Sanji can guess that as many as three rows of burials would be affected by the pull of the moon, on the highest tides of the year.

Eyes straining in the dim, wavering light, Sanji spots movement at the back of the chamber. A lone figure, idly pacing along the stone floor near the edge of the water. Sanji can’t tell if it has seen or heard him, but there is no sign of danger as he sneaks closer to the dry end of the chamber.

It’s some kind of ceremonial space, dropping in shallow tiers from a wide platform above the level of even the highest tides, with a large podium centered at the top. Dipping back below the water, Sanji can see where the workmanship ends, the cavern wall falling into darkness with a sharp drop-off.

The music is definitely coming from the figure, Sanji concludes, swimming closer as it paces away. It has some kind of human instrument, mostly blocked from sight by its bushy, dark hair. Not exactly threatening, and Sanji is wondering how to announce himself when it turns back his way.

The figure is a human skeleton. Sanji has seen enough of them in shipwrecks, but he’s never seen one _move_. He’s all but ready to dive back underwater and get out of here, but the moment the skeleton lays eyes on him - or, spots him, Sanji supposes - it gives a delighted laugh, the sound honest enough that Sanji can’t feel frightened.

“Ohoho! A living, breathing merperson! I never thought I would see the day!”

Sanji doesn’t know what to say to that, but crosses the last shallow tier of stone to the edge where the skeleton is standing. It’s hard to tell, but he thinks its gangly form is considerably taller than the humans Sanji has met thus far. Lowering its instrument - a configuration of wood and strings that Sanji cannot imagine making the eerily beautiful music filling the cavern - the skeleton crouches down next to him.

“After all my time here, of course I knew you existed, but I had imagined that perhaps your people went extinct in ages past,” the skeleton continues, with a melodic laugh. “Not that I am one to speak of dying out!”

“Right,” Sanji slowly says, uncertain how to respond to the idea of his entire race going extinct. The skeleton seems to notice, somehow looking abashed despite not having a face.

“But how rude of me! Ohoho, after so long alone, it seems my social graces have rotted away with my skin! Please forgive an old man, my dear.”

“Of course,” Sanji pauses, looking around the bare platform. “How long have you been here?”

“Well, difficult as it is to keep time by the passing of the tides,” the skeleton hedges, “why, decades at least. Perhaps you’ll stay to pass the time with me a while?”

“I have some time,” Sanji agrees. Enough to figure out what in the world is going on here, at least.

“Lovely!” The skeleton exclaims. “I am afraid I have nothing to offer you, unless you would enjoy a song? But do come up, my dear - I believe you will be surprised!”

With a mental shrug, Sanji drags himself out of the water. At the top of the next platform, there are basins hewn into the rock, full of fresh seawater left by the tide. Splashing into one, Sanji finds its edges smooth and comfortable, the elegant patterns carved around it worn soft by centuries of waves. Perhaps by fingers too, Sanji muses, running his own along the whirls.

The skeleton watches him curiously at first, but politely looks away while Sanji struggles to the top, ambling over only once he’s comfortable in the basin.

“Only the highest tier stays _bone_ dry, ohoho,” the skeleton softly laughs. “It seems whoever built this place did so with the comfort of both your own people and humans in mind.”

“What is this place?”

“Your guess is as good as mine! Despite being the only living dead in this place of eternal rest, I have no deeper understanding of it. Indeed, to guess by the pictures on the walls, this was quite the destination for the dearly departed, but I have only the evidence of my eyes to speak of. Though I have no eyes! Skull joke!”

Somewhat taken aback by the skeleton’s humor, Sanji lets that question slide. “Then, what are you doing here?”

The skeleton gives a sad little shrug, gesturing at the empty stone and dark water. “As you can see... Let me tell you, it is impossible to keep a violin in tune down here. But I make do, ohoho!”

“Sorry,” Sanji winces. “You… can’t leave?”

“If only!” The skeleton laughs again, and already Sanji can hear the pain in the sound. “I am afraid that my return from death was not the blessing I expected. Are you familiar with Devil Fruits? I survived the disaster that took my crew, but it left me trapped here amongst the dead.”

“I’m… sorry to hear that,” Sanji offers, hating the inadequacy of it.

“It was a long time ago,” the skeleton says. “There is no reason to speak of such old news. Tell me, my dear, what brings you here? No one has ventured into this place for as long as I have been the sole animated occupant of it.”

“A treasure map,” Sanji explains. “I came here with friends, some human friends. Their boat can’t fit through the tunnel until low tide, so I came in to explore.”

The skeleton makes a low noise, bone fingers worrying at the neck of his instrument. “Oh dear.”

“What happened to your crew?” Sanji asks, dreading the answer. “The disaster you mentioned…”

“Much like you, we followed rumors of treasure,” the skeleton hums. “But no treasure is left unguarded. The monster got us, I am afraid. I can only guess what fate befell our ship.”

Recalling the graveyard of ships outside, Sanji can feel himself go pale. “What monster?!”

“I have not seen it since my resurrection, but surely you noticed that no fish swim in this cavern, that nothing lives in these waters? A dreadful creature it must be indeed.”

“Maybe it’s dead,” Sanji nervously suggests, eyeing the impenetrable black in the center of the cavern. “Or gone.”

“My dear, do you really believe that?”

The soft tone of regret in the skeleton’s voice is jarring, and as Sanji looks into his empty eye sockets, he can’t say he does. As much as he would like to believe something so convenient, the eerie lifelessness of the water in this cave is too suggestive of the truth.

“The tide is nearly out,” the skeleton observes. “Ohoho, do you suppose your friends will follow you in?”

Sanji whips around to stare at the cavern entrance, as if he can prevent the humans from doing so by sheer force of will. Water pours out of the next row of alcoves, each receding wave leaving them drier than the last. Even as he flexes his muscles to throw himself out of the basin and race back to the boat, a chorus of familiar voices echoes down the silent tunnel.


End file.
